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NOTES 


ON   THE 


CHEMISTRY  OF  IRON 


FOR  PROFESSIONAL  MEN,  STUDENTS,  IRON  AND  STEEL  MERCHANTS. 
AND    ALL    INTERESTED    IN    IRON. 


BY 

MAGNUS   TROILIUS,  E.M, 


SECOND  EDITION,  REVISED  AND  ENLARGED. 


RK: 

JOHN   WILEY   &   SONS,  PUBLISHERS. 

1886. 


COPYRIGHT,  1885, 
BY  MAGNUS  TROILIUS. 


TO  THE  MEMORY 

OF 

THE  LATE  MR.  ALEX.  L.  HOLLEY 

THIS  BOOK 

is 
DEDICATED. 

"  He  visits  America     ...     to  see  what  is  doing    .     .     .     and  to  contribute, 
if  he  can,  in  the  matter  of  a  uniform  system  of  analysis  of  steel." 

(Extract  from  a  general  letter  of  introduction  written  for  the  Author  by  Mr.  Holley  in  London,  December 
12,  1881.) 


PREFACE. 


IN  presenting  this  little  work  to  the  public,  the  author  has 
endeavored  to  embody  in  plain  language  a  thoroughly  practical 
description  of  such  chemical  methods  of  analysis  in  iron  and 
steel  manufacture  as  have  come  under  his  personal  observation 
during  some  years  of  practice. 

It  is  hoped  that  their  special  adaptation  to  their  purpose  will 
be  at  once  recognized,  and  their  combination  of  rapidity  with 
accuracy  noted. 

Wrought  iron  and  steel,  being  of  special  interest  at  this 
time,  have  been  particularly  prominent  in  the  work. 

The  methods  of  analysis  having  been  explained,  the  reader 
is  also  shown  how  to  apply  the  results  obtained ;  and  thus  the 
practical  character  of  the  work  is  at  once  established. 

The  thanks  of  the  author  are  due  to  Mr.  R.  W.  Davenport, 
Superintendent  of  the  Midvale  Steel  Company,  for  valuable 
advice;  and  to  Mr.  E.  Hallgren,  C.E.,  for  labor  bestowed  on 
the  drawings. 

It  is  hoped  that  the  principles  and  practice  here  set  forth 
will  prove  of  assistance  to  iron  and  steel  manufacturers  and 
better  enable  them  to  meet  the  severe  demands  made  upon 
their  products  in  this  age  of  progress.  If  such  be  in  any 
measure  the  result  of  his  efforts,  none  will  be  better  pleased 

than  the 

AUTHOR. 


PREFACE  TO  THE  SECOND  EDITION. 


THE  first  edition  being  exhausted,  a  second  was  called  for 
and  is  herewith  published. 

Several  additions  and  enlargements  have  been  made,  and 
the  Author  wishes  to  express  his  thanks  to  all  those  who  have 
lent  their  friendly  criticism  and  advice  in  working  out  the 
same. 

Mr.  O.  L.  Kehrwieder,  late  my  assistant  at  the  Midvale 
Steel  Company,  has  contributed  the  list  of  requisites  for  an 
Iron  Laboratory,  and  also  successfully  worked  out  the  details 
of  the  method  for  determining  aluminium  in  alloys  with  iron, 
etc.,  suggested  by  the  Author. 

A  list  is  given  of  chemists  whose  labors  have  been  more 
or  less  associated  with  some  of  the  methods  described  in  this 
book. 

The  chapter  on  Gas  Analysis  has  been  extended  ;  chapters  on 
Electrolysis  and  Metallurgical  Applications  have  been  added, 
and  the  Appendices  have  received  numerous  additions. 

MAGNUS   TROILIUS. 
PHILADELPHIA,  March,  1886. 


CONTENTS. 


CHAPTER   I. 

PAGE 

GENERAL  REMARKS  REGARDING  THE  DISTINCTIVE  PROPERTIES 
OF  PIG-IRON,  WROUGHT  IRON  AND  STEEL,  AND  THE  INFLU- 
ENCE OF  THE  VARIOUS  ELEMENTS  USUALLY  COMBINED  AND 
ALLOYED  WITH  THE  SAME  .  „  .  4-  .  .  .  I 

CHAPTER   II. 

DETERMINATION  OF   ELEMENTS  MOST  FREQUENTLY  OCCURRING 

COMBINED    OR   ALLOYED    WITH    IRON. 

A.  Analysis  of  Wrought  Iron  and  Steels          .     •    '.    ''"' ._       ',.     ^ 

a.  Determination  of  Carbon  by  Combustion  in  Oxygen  .       7 

b.  Determination  of  Carbon  by  Combustion  with  Chro- 

mic and  Sulphuric  Acids          .         .  .  .  .16 

c.  Other  Combustion  Methods  for  Carbon  .  .  .18 

d.  The  Determination  of  Carbon  by  Color  .  .  .     19 

e.  Determination  of  Phosphorus      .         .  .  .  .     23 

f.  Determination  of  Manganese      .         .         .       ...         .     29 

g.  Determination  of  Silicon    ......     35 

h.  Determination  of  Sulphur  ......     36 

/.  Determination  of  Copper   ......     39 

j.  Determination  of  Slag  and  Oxide  of  Iron  .         .         .41 
k.  Determination  of  Arsenic   ......     44 

/.  Determination  of  Titanium          .         .         .         .         -45 

m.  Tracing  of  Vanadium          .         „  .         .         .46 

n.  Determination  of  Chromium       .         .         .         .         .46 

o.  Determination  of  Tungsten         .         ...         .         .48 


Yin  CONTENTS, 


FAGE 


B.  Analysis  of  Pig-iron    .       /.  •  ,    *        .        .        .        .  .     49 

a.  Determination  of  Graphite       .   .         .      -.      " '.."  .     49 

b.  Determination  of  Silicon    .         .  *•     .         .        »  .     49 

c.  Determination  of  Sulphur  .      y.y      .   ..     .       ;.  .     50 

d.  Slag    .         .        -.        . .,       .         .         .         .        /  .  .     50 

C.  Analysis  of  Spiegel  and  Ferromanganese    .         .         .  .     50 

D.  Analysis  of  Silicon-iron,  etc.       .         .         *         ,         4  .     53 

CHAPTER   III. 

DETERMINATION  OF  THE  MOST  IMPORTANT  INGREDIENTS  IN   IRON 
ORES,  SLAGS,  LIMESTONES,  FUEL,  ETC. 

A.  Analysis  of  Iron  Ores          .         .  .     V        .         .         .  "  .     55 

a.  Determination  of  the  Total  Iron          .         .        >  •.     55 

b.  Determination  of  the  Iron  present  as  Ferric  Oxide  .     57 

c.  Determination  of  Phosphorus     .       ..         ,         .'  .     58 

d.  Determination  of  Sulphur.         ^        .         »    ,     .  -59 

e.  Determination  of  Manganese      .         .;       .    '     .  .     60 

f.  Determination  of  Moisture  and  Loss  on  Ignition  .     60 

g.  Complete  Analysis  of  Iron  Ores         .         .         .  .61 
h.  Elements  of  Rare  Occurrence    .        ,  .     *         .  .68 

i.  The  Dry  Assay  of  Iron  Ores       .         .        »        ,  .     70 

B.  Analysis  of  Slags,  etc.       ;.         .;     >        ...      .         ,r  .     72 

C.  Analysis  of  Coal  and  Coke       .    .         .      .»       ,«         .  -73 

CHAPTER    IV. 
NOTES  ON  GAS  ANALYSIS    .     ' 76 

CHAPTER   V. 

METALLURGICAL  NOTES  AND  PRACTICAL  USES  OF  THE  RESULTS 
OF  ANALYSES 95 

CHAPTER   VI. 

NOTES  ON  ELECTROLYSIS ;.  .   107 


CONTENTS.  IX 

PAGE 

APPENDICES 113 

A.  Heat  Calculations      .         .         .         .         .    .     .  .  -115 

B.  Calculation  of  Blast-furnace  Burden  .         .         .  .  .121 

C.  Table  for  Rapid  Calculation  of  Analyses   .         ,  ,  .124 

D.  Etching  Test .  .125 

E.  Table  of  Elements „  .  .126 

F.  French  Weights  and  Measures   .         .         .         .  .  .127 

G.  "  Body  in  Steel" 129 

H.  Melting  Points,  etc.  .         .         .         .         .         .  .  .   131 

/.  Laboratory  Requisities •.  .132 

J.   Iron  Ores  ......         .         .  .  .   137 

K.  Organic  Matter  in  Water   .         .         .         .         .  .  -139 

L.  Table  Giving  the  Tension  of  Aqueous  Vapor     .  .  .141 

M.  Useful  Tables .  142 


NOTES  ON  THE  CHEMISTRY  OF  IRON. 

J%K£&&. 

•U  in 

CHAPTER   I.' 


GENERAL  REMARKS  REGARDING  THE  DISTINCTIVE  PROPER- 
TIES OF  PIG-IRON,  WROUGHT  IRON,  AND  -  STEEL,  AND  THE 
INFLUENCE  OF  THE  VARIOUS  ELEMENTS  USUALLY  COM- 
BINED AND  ALLOYED  WITH  THE  SAME. 

BY  pig-iron  we  mean  the  metal  obtained  by  the 
reduction  of  iron  ores  in  the  blast-furnace.  Pig-iron  is 
used  as  raw  material  in  the  manufacture  of  wrought 
iron  and  steel :  it  is  also  largely  used  for  making  cast- 
ings. The  chemical  composition  of  pig-iron  varies  ac- 
cording to  the  purposes  for  which  it  is  intended.  In 
the  blast-furnace  are  also  manufactured  various  alloys 
of  iron  with  manganese  (spiegel,  ferromanganese),  and 
alloys  of  iron  with  silicon,  or  with  both  silicon  and 
manganese  ("  ferro  silicium,"  "  special  pig  "). 

By  wrought  iron  we  mean  the  metal  obtained  from 
processes  such  as  the  Swedish  Lancashire,  Catalan,  and 
puddling,  in  which  processes  the  refined  metal  does  not 
occur  in  a  fluid  condition.  Wrought  iron  always  con- 
tains a  considerable  amount  of  slag  and  oxides  of  iron 
in  mechanical  admixture.  By  steel  we  mean  the  metal 


2  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

obtained  from  the  crucible,  Bessemer,  Siemens,  and 
other  processes,  where  the  refined  metal  is  obtained  in 
a  fluid  condition,  and  can  be  cast  into  moulds.  Steel 
seldom  contains  more  than  a  very  small  amount  of  oxide 
of  iron  and  slag. 

We  have  further  to  note  so-called  malleable  iron  cast- 
ings. Such  castings  are  made  of  pig-iron  of  suitable 
chemical  composition.  By  heating  such  castings  in 
oxidizing  substances  (oxides  of  iron,  etc.),  excess  of  car- 
bon is  eliminated,  and  the  metal  is  rendered  malleable. 

The  elements  which  most  usually  occur  in  pig-iron, 
wrought  iron,  steel,  etc.,  are  carbon,  phosphorus,  man- 
ganese, silicon,  sulphur,  copper,  chromium,  and  tungsten. 
More  seldom  there  is  found  arsenic,  antimony,  nickel, 
and  cobalt.  Chromium  and  tungsten  mostly  occur  in 
the  special  steels  named  after  said  elements.  Titanium 
and  vanadium  are  occasionally  found.  Slag  and  oxide 
of  iron  are  of  importance  in  many  cases.  Iron  and  steel 
also  contain  more  or  less  hydrogen,  nitrogen,  carbonic 
oxide,  and  other  gases.  For  these  we  have  no  really 
practical  methods  of  analysis. 

As  to  the  influence  of  the  various  elements  above 
mentioned  on  the  properties  of  iron  and  steel,  it  is  only 
with  regard  to  the  eight  first  that  we  possess  much 
accurate  knowledge.  No  unvarying  rules,  however,  can 
be  laid  down.  The  reason  for  this  lies  in  the  nature 
and  conditions  of  the  various  processes  of  manufacture. 
Besides  the  many  external  and  physical  forces  that  tend 
to  modify  the  influence  of  chemical  composition,  such 


INFLUENCE    OF    VARIOUS    ELEMENTS.  3 

as  rolling,  hammering,  hardening,  and  annealing,  there 
may  be  formed,  at  various  temperatures  and  under  va- 
rious circumstances,  innumerable  chemical  compounds 
of  different  molecular  structure.  These  compounds 
may  again  split  up  into  others,  when  changes  occur  in 
the  said  conditions.  These  phenomena  are  analogous 
to  those  so  well  known  in  the  dissociation  of  gases. 
Castings  often  have  different  chemical  composition  in 
different  parts.  This  is  due  to  the  separation  of  such 
compounds.  When,  therefore,  we  determine  the  total 
amounts  of  carbon,  silicon,  etc.,  in  iron  and  steel,  and 
try  to  define  their  relations  to  physical  properties,  we 
must  bear  in  mind  that  we  may  not  know  the  compo- 
sition of  the  various  compounds  or  alloys  which  said 
elements  have  formed  in  the  metal,  and  that  these  com- 
pounds and  alloys  may  be  different  in  steels  of  the 
same  chemical  composition.  Thus  the  physical  prop- 
erties of  apparently  similar  steels  may  differ  widely. 

Iron  forms  alloys  in  any  proportions  with  manganese, 
chromium,  tungsten,  nickel,  cobalt,  copper,  gold,  plati- 
num, aluminium,  antimony,  silicon,  sulphur,  phosphorus, 
and  arsenic :  in  limited  proportions  only  with  zinc,  tin, 
bismuth,  and  carbon.  It  scarcely  alloys  at  all  with  lead, 
silver,  and  mercury. 

Influence  of  Carbon.  We  have  to  consider  carbon 
as  occurring  in  iron  in  at  least  two  distinct  forms  or  con- 
ditions, —  "  graphitic  "  and  "  combined  carbon."  Graph- 
itic carbon  occurs  almost  exclusively  in  gray  pig-iron, 
taking  the  form  of  dark,  thin  flakes,  varying  much  in 


4  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

size,  and  intersecting  the  molecules  or  small  particles 
of  iron.  Its  influence  is  to  make  the  pig-iron  softer 
and  tougher  than  would  be  the  case  if  it  existed  in  the 
form  of  "  combined  carbon." 

"  Combined  carbon "  is  now  generally  supposed  to 
occur  under  two  distinct  forms.  The  one,  so-called 
"  cement  carbon,"  consists  of  alloys  of  iron,  carbon,  and 
a  little  silicon,  uniformly  distributed  or  dissolved  in 
the  metal.  The  other  is  the  so-called  "hardening  car- 
bon." The  cement  carbon  remains  as  a  black  residue 
when  the  metal  is  dissolved  in  cold  acids,  whilst  the 
hardening  carbon  passes  off  as  hydro-carbon  gases  of 
the  ethylene  (C2  H4)  series.  By  heating  iron  or  steel  to 
a  red  heat,  and  rapidly  cooling  in  water,  the  cement 
carbon  is  converted  into  hardening  carbon.  Simply 
hammering  cold  has  the  same  effect  to  some  extent. 
Slow  cooling  or  annealing  produces  cement  carbon. 
Doubtless  these  phenomena  can  be  classed  with  those 
referred  to  above,  as  analogous  to  the  dissociation  of 
gases.  It  is  therefore  evident,  that  simply  the  knowl- 
edge of  the  amount  of  total  carbon  is  not  enough  to 
explain  the  physical  influence  of  the  same.  In  general, 
we  may  say  that  the  tensile  strength  of  steel  increases 
with  the  combined  carbon  up  to  about  one  per  cent, 
again  decreasing  as  the  carbon  increases  above  this 
point.  The  elastic  limit  is  raised  by  combined  carbon 
somewhat  more  rapidly  than  is  the  tensile  strength. 

Influence  of  Silicon.  In  the  manufacture  of  pig- 
iron  in  the  blast-furnace,  silicon  replaces  carbon  to  some 


INFLUENCE    OF    VARIOUS    ELEMENTS.  5 

extent,  and  promotes  the  production  of  gray  pig-iron, 
i.e.,  the  formation  of  graphitic  carbon.  Otherwise  its 
influence  in  iron  and  steel  is  similar  to  that  of  carbon, 
but  less  active. 

Influence  of  Phosphorus.  Phosphorus  is  consid- 
ered to  exist  in  irons  and  steels  as  the  phosphide  of  iron 
(Fe4  P2).  There  are  many  other  iron  phosphides  known : 
but  the  one  represented  by  the  above  formula  is  the  poor- 
est in  phosphorus  of  them  all,  and  may,  therefore,  be  con- 
sidered as  being  dissolved  in  an  excess  of  metallic  iron. 

Phosphorus  causes  cold-shortness,  i.e.,  brittleness 
when  cold;  and  the  more  so  the  greater  the  amount 
of  carbon  present.  The  presence  of  silicon,  on  the  other 
hand,  carbon  being  absent,  appears  to  modify  to  a  con- 
siderable degree  the  effect  of  phosphorus  to  cause  cold- 
shortness.  Advantage  is  sometimes  taken  of  this  fact, 
when  a  large  amount  of  phosphorus  is  present,  to  ob- 
tain hardness  in  steel  by  replacing  carbon  with  silicon. 
Both  carbon  and  silicon  render  the  metal  more  fusible, 
but  phosphorus  does  so  in  a  much  higher  degree.  Phos- 
phorus, especially  in  steel,  has  a  great  tendency  to  ren- 
der the  metal  crystalline. 

Influence  of  Sulphur.  Sulphur  occurs  in  iron  and 
steel  as  the  monosulphide  of  iron  (Fe  S).  Sulphur 
opposes  the  absorption  of  carbon  in  the  blast-furnace 
process,  but  promotes  the  formation  of  combined  carbon. 
Sulphur  makes  wrought  iron  and  steel  red-short,  i.e., 
brittle  at  a  red  heat ;  but  its  direct  influence  on  the  cold 
metal  when  present  in  moderate  quantities  is  doubtful. 


6  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

Influence  of  Manganese.  Manganese  aids  the  ab- 
sorption of  carbon  in  the  blast-furnace  and  the  formation 
of  combined  carbon.  The  influence  of  manganese  on 
wrought  iron  and  steel  varies  with  the  other  ingredients. 
It  seems  to  act  like  carbon  in  most  cases,  though  with 
less  energy,  and  to  make  the  metal  more  easily  worked 
at  a  forging  heat.  It  is  thus  a  remedy  for  sulphur, 
whilst  it  acts  indifferently,  like  silicon,  towards  phos- 
phorus. In  the  manufacture  of  steel,  manganese  is 
added  at  the  end  of  the  process  to  remove  oxygen  from 
the  bath.  An  addition  of  both  manganese  and  silicon 
prevents  blow-holes  in  steel. 

Influence  of  Copper.  Not  much  is  known  regard- 
ing the  effect  of  this  element.  Some  red-shortness 
seems  to  be  caused  by  the  presence  of  a  high  per- 
centage of  copper. 

Oxygen  in  Steel  causes  red-shortness,  and  is  con- 
sidered to  exist  chiefly  as  the  iron  mon-oxide  (Fe  O). 
In  wrought  iron  it  occurs  in  the  slags  of  various  com- 
position that  enter  into  that  metal. 

Influence  of  Chromium  and  Tungsten.  Both 
these  elements  render  the  metal  very  hard.  Chromium 
has  more  effect  than  tungsten.  Chromium  steel  seldom 
contains  more  than  one  per  cent  of  chromium,  whilst 
tungsten  steel  often  has  nine  per  cent  of  tungsten. 
Both  chromium  and  tungsten  steels  are  mostly  used  for 
cutting  tools,  etc.  Chromium  steel  is  also  occasionally 
used  for  structural  purposes. 


CHAPTER    II. 

DETERMINATION    OF    ELEMENTS    MOST     FREQUENTLY     OCCUR- 
RING    COMBINED    OR    ALLOYED    WITH    IRON. 

A. — Analysis  of  Wrought  Iron  and  Steels. 

THE  analysis  of  wrought  iron  and  steels  is  first  con- 
sidered, because  the  greatest  possible  accuracy  is  therein 
required  and  the  methods  must,  therefore,  be  described 
in  full  detail.  These  same  methods  apply  as  a  rule 
to  the  analysis  of  pig-irons,  spiegel,  ferromanganese, 
etc.  The  slight  modifications  that  are  necessary  will 
be  subsequently  mentioned. 

a.  Determination  of  Carbon  by  Combustion  in 
Oxygen.  Five  grams  of  drillings  are  weighed  out  and 
put  into  a  flask  of  somewhat  more  than  three  hundred 
cubic  centimetres  capacity.  The  flask  should  be  of 
thick  glass.  It  must  have  a  ground  stopper  and  lip 
to  facilitate  pouring.  A  few  drops  of  ammonia  are  put 
into  the  flask  before  putting  the  drillings  into  the  same. 
The  drillings  must  be  prepared  with  care  so  as  to  con- 
tain no  combustible  matter.  They  should  be  extracted 
with  a  magnet  when  weighing  out.  Upon  the  drill- 
ings is  poured  a  solution  of  the  double  chloride  of 

copper   and    ammonia   (/NH  \  r  ClA     This    solution    is 


8  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

prepared  by  dissolving  one  part  by  weight  of  the  salt 
in  three  parts  of  water,  filtering  it  through  a  purified 
asbestos  filter  and  adding  ammonia  to  the  filtrate  until 
a  slight  permanent  precipitate  is  obtained.  Three  hun- 
dred cubic  centimetres  of  this  solution,  with  the  green 
permanent  precipitate  well  shaken  up  in  it,  is  used  for 
five  grams  of  drillings.  The  stopper  is  inserted  and 
the  flask  kept  in  agitation  until  all  the  separated  copper 
has  completely  disappeared.  The  solution  then  be- 
comes very  neutral  and  a  basic  salt  separates  which  is 
readily  dissolved  in  a  few  drops  of  hydrochloric  acid. 
The  residue  contains  all  the  carbon,  some  silica,  and 
possibly  some  iron-phosphide,  etc.  When  a  large  num- 
ber of  determinations  have  to  be  made  it  is  convenient 
to  have  many  flasks  marked  differently.  The  flasks 
may  then  be  placed  in  a  shaking  apparatus  (Fig.  I.), 
which  consists  of  a  board  with  holes,  into  which  the 
flasks  are  wedged.  This  board  is  supported  by  up- 
rights, one  at  each  corner.  The  uprights  have  uni- 
versal joints  at  both  ends,  so  that  the  board  can  be 
agitated  in  a  circular  direction  at  a  rapid  rate  without 
revolving  or  twisting  in  any  way.  Under  the  board 
and  attached  to  it  at  the  centre  is  a  projecting  pin 
moving  in  an  arm.  This  arm  is  attached  to  a  vertical 
spindle  which,  when  revolved  by  means  of  a  crank  and 
bevelled  gears,  agitates  the  board.  The  arm  has  a 
perforation  by  means  of  which  the  projecting  pin 
under  the  board  is  held  at  about  three  inches  from 
the  centre  of  the  spindle.  The  apparatus  may  be  driven 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS.  9 

by  a  small  water  or  gas  motor  or  by  hand.     By  using 


o  o 


0  O 


n  n  n 


\  1  \ 

1 

\ 

-T=tt= 

/  \  i  \  rt 

FIG.  I. 


v              v  'x 

' 

s  *            V 

^.      ^*- 

- 

-    / 

^  - 

^  s 

r 

^\ 

* 

this  apparatus  a  large  number  of  samples  may  be  com- 


10 


NOTES    ON    THE    CHEMISTRY    OF    IRON. 


S6 


pletely  dissolved  in  less  than   one  hour,  particularly  if 
the  borings  be  fine.     The  reaction  is  principally  — 

Fe  +  2  Cu  C12   =   Fe  C12  +  Cu2  C12. 

Some  copper  separates    at   first  but    is    afterwards    re- 
dissolved  on  shaking: 

Fe  +  Cu  C12   =   Fe  C12  +  Cu. 
Cu  +  Cu  C12   =    2  Cu  Cl. 

After  allowing  at  least  one  hour  for  the  settling  of  the 
carbon  residues,  they  are  filtered  off  into  platinum  fun- 
nels, of  shape  shown  by  Fig.  II. 
At  the  bottom  of  the  funnel  is  a 
coil  of  platinum  wire  to  support 
the  asbestos  filter.  This  asbestos 
must  be  purified  before  using  by 
washing  with  hydrochloric  acid 
and  igniting,  —  best  in  a  current 
of  oxygen  or  air.  A  good  way  is 
to  prepare  a  filter  of  impure  as- 
bestos and  ignite  it  in  a  stream 
of  oxygen  in  the  combustion-tube. 
The  filter  once  thus  prepared  will 
last  for  many  determinations,  un- 
less it  should  happen  to  become 
T  badly  clogged.  In  this  case  the 

asbestos  may  be  shaken  out,  loos- 
ened, and  put  back  again.  The 
funnel  is  inserted  into  one  of  the 

necks    of   a   two-necked  flask   by   means    of   a    rubber- 
stopper  and  suction   applied    through   the   other  neck 


Mcy, 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS. 


II 


by  means  of  a  good  water  suction- 
pump.  By  means  of  a  glass  rod 
the  filter  is  packed  carefully  and 
tightly  and  filtering  proceeded 
with.  When  the  residue  reaches 


Fixed  To 


Table. 


FIG.  III. 


the  filter  the  operation  is  often 
much  retarded  owing  to  the 
clogging  properties  of  some  car- 
bon residues.  With  good  suction 
and  some  practice,  however,  this 
does  not  cause  serious  difficulty. 
The  residue  is  first  washed  with 
a  little  hydrochloric  acid  and 


12  NOTES    ON    THE    CHEMISTRY    OF   IRON. 

- 

finally  with  plenty  of  hot  water.  The  acid  must  be 
used  before  using  water.  Water  alone  causes  a  white 
precipitate  of  sub-chloride  of  copper  which  clogs  the 
filter  badly.  The  platinum  funnels  with  their  contents 
are  dried  at  100°  C.  in  an  ordinary  drying-box.  When 
dry,  —  which  is  indicated  by  the  shrinking  of  the  black 
mass  on  the  filter,  —  the  residues  are  ready  for  com- 
bustion. Fig.  IV.  shows  the  general  arrangement  of 
the  combustion-apparatus,  and  Fig.  III.  shows  the  cor- 
rect dimensions  of  the  combustion-tube  (of  platinum), 
with  an  air-tight  joint  of  brass  at  one  end. 

Two  things  are  essential  for  the  successful  use  of  this 
apparatus.  Firstly,  absolute  purification  of  the  oxygen 
and  air.  Secondly,  absolute  tightness  of  the  apparatus 
in  all  parts.  The  first  condition  is  fulfilled  by  passing 
oxygen  and  air  through  very  capacious  jars  filled  with 
sulphuric  acid,  fluid  potash,  and  solid  potash,  respec- 
tively. The  second  condition  can  only  be  met  by  using 
the  greatest  care  in  fixing  the  rubber-stoppers  and  rub- 
ber-tubings on  to  the  apparatus. 

On  Fig.  IV.  the  oxygen  receiver  A,  containing  com- 
pressed oxygen,  is  seen  standing  on  the  floor.  From 
this  receiver  the  oxygen  passes  through  the  safety- 
bottle  B  into  the  bottle  B\  containing  a  solution  of 
potash  (three  weights  of  potash  in  five  weights  of  water). 
B  and  B^  have  a  capacity  of  two  liters  each.  Simi- 
larly arranged  are  the  bottles  C  and  Ci  containing 
concentrated  sulphuric  acid.  They  are  each  of  one 
liter  capacity.  The  safety-bottles  prevent  the  liquids 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS. 


from  mixing  in  case  of   back-pressure  and  from  going 
down  into  the  receiver.     The  oxygen  finally  passes  up 


through  a  jar  D  of  about  two  liters  capacity,  filled 
with  pieces  of  solid  potassium  hydrate.  This  arrange- 
ment effects  a  very  durable  and  reliable  purification 


14  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  the  oxygen,  freeing  it  from  the  last  traces  of  moist- 
ure and  carbonic  acid.  An  exactly  similar  arrange- 
ment (not  shown  on  Fig.  IV.)  is  had  for  the  air  which 
is  pressed  through  the  apparatus  after  each  combustion 
to  expel  the  oxygen.  A  three-way  glass  tube  connects 
the  combustion-tube  with  the  two  potash-jars,  for  each 
of  which  there  is  a  glass  stop-cock;  thus  the  oxygen 
and  air  purifiers  can  be  shut  off  and  connected  alter- 
nately at  will.  Where  blast  is  available  it  can  be 
conveniently  used  to  press  air  through  the  apparatus. 
It  is  better  to  press  air  through  than  to  draw  it  through, 
the  risk  of  drawing  in  impure  air  through  some  small 
leak  being  obviated.  The  platinum  tube  contains,  at 
the  end  where  its  diameter  is  diminished,  a  roll  of 
platinum  gauze  four  inches  long.  This  gauze  insures 
the  conversion  of  any  carbonic  oxide  to  carbonic  acid 
during  the  combustion.  The  platinum  tube  is  con- 
nected with  the  Marchand's  tube  M  filled  with  small 
pieces  of  pumice-stone  which  have  been  thoroughly 
soaked  with  cupric  sulphate  and  then  heated  'to  about 
230°  C.  The  white  anhydrous  cupric  sulphate  thus 
obtained  absorbs  moisture  and  traces  of  hydrochloric 
acid  gas  very  rapidly,  turning  gradually  blue.  When 
it  has  become  decidedly  blue  in  color  it  should  be 
replaced  by  fresh  pumice.  A  little  hydrochloric  acid 
gas  as  well  as  some  chlorides  are  generally  volatilized 
during  the  combustion,  even  after  the  most  thorough 
washing  of  the  carbon  residue.  A  little  jar  K  filled 
with  pieces  of  chloride  of  calcium  is  connected  with 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  15 

the  Marchand's  tube.  The  porous  calcium  chloride 
should  be  used,  not  the  fused,  the  latter  being  apt  to 
contain  some  calcium  oxide  which  absorbs  carbonic 
acid.  The  porous  calcium  chloride  offers  more  surface 
to  the  passing  gases  and  absorbs  moisture  more 
quickly.  Between  this  jar  and  the  similar  jar  K\, — 
the  so-called  safety-jar  rilled  with  pieces  of  potash, 
—  the  absorption-bulbs  R  are  inserted.  The  safety- 
jar,  which  is  the  least  important  part  of  the  whole 
apparatus,  prevents  the  entrance  of  impure  air  at  the 
end  of  a  combustion,  when  a  slight  back-pressure  is 
apt  to  take  place.  The  bulbs  R  are  made  after  the 
Geissler  pattern,  with  the  modern  improvement  of 
having  the  drying-tube  joined  to  the  bulbs  in  one 
piece.  The  bulbs  are  rilled  with  a  potash  solution  of 
the  same  strength  as  mentioned  above ;  the  drying- 
tube  is  filled  with  pieces  of  solid  potash.  Chloride  of 
calcium  cannot  here  be  used  effectively.  When  thus 
connected  the  apparatus  should  permit  air  being  passed 
through  it  for  hours  without  showing  any  increase  of 
weight  in  the  bulbs.  Having  ascertained  this  the 
apparatus  can  be  safely  used  for  many  weeks,  only 
renewing  the  pumice  and  the  contents  of  the  absorption- 
bulbs  occasionally. 

To  carry  out  a  combustion  the  platinum-funnel  con- 
taining the  carbon  residue  is  dropped  into  the  platinum- 
tube  with  the  narrow  end  first.  The  above-mentioned 
platinum-gauze  keeps  the  funnel  in  its  proper  position 
at  the  centre  of  the  platinum-tube.  The  joint  at  the 


1 6  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

wider  end  of  the  platinum-tube  is  closed  and  the 
weighed  absorption-bulbs  inserted  in  their  proper  place. 
The  flow  of  oxygen  is  started  at  the  rate  of  about 
three  bubbles  a  second,  and  a  couple  of  good  gas- 
burners  lit  under  the  tube  and  turned  on  full.  The 
centre  of  the  platinum-tube  may  be  covered  with  a 
piece  of  some  refractory  material  such  as  one-half  of 
an  "  Erdmann's  cylinder."  After  ten  to  twenty  minutes 
the  oxygen  is  shut  off,  the  air  put  on  and  the  gas 
turned  down.  When  the  tube  has  nearly  cooled,  the 
bulbs  are  taken  out  and  weighed  without  delay.  After 
accurately  weighing  the  bulbs  they  may  be  immedi- 
ately inserted  in  their  place  again  and  the  next  com- 
bustion proceeded  with.  It  is  quite  unnecessary  —  in 
fact  often  inaccurate  —  to  allow  the  bulbs  to  stand  any 
length  of  time  in  the  balance-case  before  weighing  them 
or  to  wipe  them  off,  as  recommended  by  some  writers. 
The  amount  of  carbon  is  found  from  the  increase  of 
weight  of  bulbs  (CO2)  by  multiplying  the  said  increase 
by  T3T,  or  .2727. 

b.  Determination  of  Carbon  by  Combustion  with 
Chromic  and  Sulphuric  Acids.  The  carbon  in  the 
residue,  after  dissolving  in  the  double  chloride  of 
copper  and  ammonia,  may  in  many  cases  be  deter- 
mined with  equal  accuracy  by  oxidizing  the  same  by 
means  of  chromic  and  sulphuric  acids  in  a  flask,  ar- 
ranged as  for  a  sulphur  determination  (Fig.  V.).  From 
this  flask  the  gas  passes  through  a  pair  of  sulphuric 
acid  bottles  arranged  as  in  Fig.  IV.  C  Ci,  and  from 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS. 


these  to  the  chloride  of  calcium  jar,  absorption-bulbs, 
and  safety-jar  exactly  as  in  the  previous  method.  In 
obtaining  the  carbon  residue  a  glass  funnel-tube  is 
used  for  filtering  instead  of  a  platinum-tube.  The 
asbestos  filter  is  supported  by  means  of  small  pieces 
of  broken  glass.  The  suction-pump  must  be  used  as 
before.  No  drying 
of  the  residue  is  re- 
quired. The  funnel 
with  its  contents  is 
placed  at  the  bot- 
tom of  the  half-liter 
flask  with  long  neck 
(Fig.  V.).  Through 
the  funnel-tube  twen- 
ty cubic  centimetres 
of  chromic  acid  solu- 
tion (one  weight  of 
chromic  acid  in  three 
weights  of  water)  is 
poured;  then  one  hun- 
dred and  fifty  cubic  centimetres  of  concentrated  sul- 
phuric acid  are  run  in  (dilute  acid  must  not  be  used). 
An  excess  of  sulphuric  acid  is  not  objectionable.  Care 
must  be  taken  that  the  sulphuric  acid  be  perfectly 
colorless  and  free  from  organic  matter.  Oxidation  of 
the  carbon  sets  in  at  once  at  a  lively  rate.  After  a 
short  time  heat  is  applied  gradually  until  the  solution 
has  turned  green,  the  evolution  of  oxygen  slackened 


FIG.  V. 


1 8  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

and  white  sulphuric  acid  fumes  have  begun  to  appear. 
The  heat  is  then  removed  and  cold  pure  air  pressed 
through  the  apparatus  until  the  half-liter  flask  has  some- 
what cooled  down.  The  absorption-bulbs  may  then  be 
weighed  and  the  next  combustion  proceeded  with.  The 
whole  operation  does  not  require  more  than  one  hour 
for  completion.  It  does  require,  however,  more  atten- 
tion than  combustion  with  the  platinum  apparatus,  and 
cannot  compare  with  this  latter  in  practical  utility. 
The  apparatus  is  cheap,  which  is  a  great  item  in  its 
favor.  Where  large  numbers  of  combustions  have  to 
be  made,  several  apparatus  and  a  large  number  of  flasks 
with  their  respective  funnels  placed  in  them  can  be 
used. 

c.  Other  Combustion  Methods  for  Carbon.  All 
those  methods  to  be  found  in  handbooks,  which  are 
based  upon  separating  the  carbon  by  means  of  ferric 
chloride,  cupric  chloride,  cupric  sulphate,  mercuric  chlo- 
ride, electricity,  etc.,  involve  a  loss  of  carbon  as  gaseous 
hydrocarbons  and  are  entirely  impracticable  and  un- 
reliable. The  use  of  the  double  chloride  of  copper  and 
ammonia  reduces  this  loss  to  a  trifling  minimum  in  most 
cases.  An  exception  occurs  in  the  treatment  of  highly 
carburetted  ferromanganeses,  for  which  direct  combus- 
tion (see  p.  50)  should  be  used.  Chromium  steel  also 
requires  direct  combustion,  being  difficult  to  dissolve  in 
the  double  chloride.  A  requisite  to  success  in  deter- 
mining  carbon  by  direct  combustion  is  to  have  the 
material  in  a  fine  state  of  division,  which  condition  can 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  19 

be  easily  attained  in  the  case  of  ferromanganeses  and 
most  chromium  steels. 

d.  The  Determination  of  Carbon  by  Color.     The 

combustion  methods  enable  us  to  determine  with  great 
accuracy  the  amount  of  carbon  in  irons  and  steels.  By 
these  methods  we  can  prepare  so-called  standard  steels, 
and  upon  the  use  of  these  is  based  the  following  color 
method :  — 

Two-tenths  of  a  gram  of  each  sample  of  drillings 
and  of  a  standard  steel  are  carefully  weighed  out  and 
placed  in  test-tubes.  It  is  advisable  to  use  a  standard  in 
which  the  carbon  is  approximately  the  same  as  that 
in  the  samples.  From  a  burette  with  glass  stop-cock 
four  cubic  centimetres  of  nitric  acid,  specific  gravity 
i. 20,  are  run  into  each  test-tube.  The  tubes  thus  filled 
are  immediately  placed  in  a  beaker,  or  tin  can,  contain- 
ing cold  water,  in  order  to  check  the  first  violent  action 
of  the  acid.  The  test-tubes  should  be  about  one 
hundred  and  thirty  millimetres  long  and  in  inside 
diameter  fifteen  millimetres.  The  beaker,  or  can,  con- 
taining the  test-tubes,  is  first  gradually  warmed,  which 
can  be  well  done  by  placing  it  for  a  quarter  of  an 
hour  on  top  of  a  boiling  water-bath.  This  water-bath 
should  consist  of  a  tin  or  copper  can  of  suitable  size, 
provided  with  a  perforated  plate  set  at  about  two 
inches  from  the  top  edge.  Through  the  perforations 
in  this  plate  the  test-tubes  are  put ;  thus,  while  resting 
on  the  bottom  of  the  bath,  they  are  steadied  by  the 
plate.  The  bath  is  then  kept  at  a  full  boil  for  about 


20 


NOTES    ON    THE    CHEMISTRY    OF    IRON. 


half  an  hour  by  means  of  a  powerful  gas-burner 
(Fletcher's).  The  tubes  are  then  taken  out,  cooled  in 
cold  water,  and  placed  in  a  test-tube  rack  ready  for 
testing.  By  the  above  operation  the  nitric  acid  solu- 
tions have  assumed  deeper  or  lighter  colors,  according 
to  the  quantity  of  carbon  present. 

For  comparing  these  colors  with  the  standard,  we  make 
use  of  three  graduated  tubes  of  thirty-five  cubic  centi- 
metres capacity  and  thir- 
teen millimetres  internal 
diameter.  These  tubes 
should  be  of  the  whitest 
glass  and  exactly  similar 
in  all  respects.  They  are 
graduated  into  tenths  of 
cubic  centimetres.  In  gen- 
eral working  only  two  of 
the  tubes  are  used,  one 
for  the  standard,  and  one 
for  the  sample,  the  third 

tube  being  held  in  reserve  for  a  second  standard  of 
different  dilution  and  color,  for  very  accurate  work. 

A  good  light  is  of  importance ;  this  is  best  obtained 
in  a  room  with  a  single  window  facing  north.  A 
camera,  made  of  blackened  wood,  as  shown  in  Fig.  VI., 
is  very  useful  for  securing  a  uniform  light.  One  end 
of  the  camera,  towards  the  light,  is  closed  by  means 
of  a  piece  of  ground  glass.  The  tubes  are  inserted 
through  a  hole  in  the  top  of  the  camera  and  held  up 


FIG.  VI. 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  21 

against  the  ground  glass  at  a  short  distance  from  the 
same.  The  camera  is  of  great  use  for  making  de- 
terminations at  night. 

To  most  eyes  the  left-hand  tube  appears  a  little  the 
darker.  The  rule  should  therefore  be  to  first  hold  the 
standard  to  the  left  and  note  when  the  test,  on  chang- 
ing it  from  right  to  left  after  each  successive  dilution 
with  water,  shows  a  very  faintly  darker  shade  than  the 
standard.  After  these  general  remarks  the  operation 
is  easily  understood. 

Suppose  the  standard  steel  contain  .84  per  cent  of 
carbon.  .We  dilute  it  then  with  water  to  16.8  cubic 
centimetres.  Two-tenths  of  a  gram  of  drillings  having 
been  used,  each  cubic  centimetre  will  thus  correspond  to 
"iV.f1"  —  -0001  gram  of  carbon;  or,  in  other  words,  to 
one-tenth  of  one  per  cent  of  one-tenth  of  a  gram  of  steel. 

Suppose  further  that,  on  diluting  the  test  to  14  cubic 
centimetres,  we  find  the  color  of  the  test  yet  slightly 
darker  than  that  of  the  standard ;  but,  on  diluting  to 
15  cubic  centimetres,  we  find  the  test  somewhat  lighter 
than  the  standard.  It  is  then  evident  that  our  test  con- 
tains more  than  .70  per  cent  (.1  X  -V")  °^  carbon,  but 
less  than  .75  per  cent  (.1  X  V')-  The  steel  can  thus 
with  safety  be  assumed  to  contain  .72  or  .73  per  cent 
of  carbon. 

This  is  the  only  way  of  using  the  color-test  that  has 
proved  thoroughly  reliable  in  practical  working,  it  being 
easily  mastered  by  any  boy  of  average  intellect.  To 
use  a  smaller  quantity  of  drillings  than  two-tenths  of 


22  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

a  gram  multiplies  the  errors  from  weighing  and  compar- 
ing of  color  and  must  be  condemned.  It  is  far  easier 
to  see  when  two  shades  of  color  differ  slightly,  than 
to  catch  the  point  where  they  are  exactly  alike.  Unless 
the  operator  can  do  this,  however,  he  cannot  work  suc- 
cessfully on  less  than  two-tenths  of  a  gram.  On  the 
other  hand,  it  is  not  desirable  to  use  more  than  two- 
tenths  of  a  gram,  as  then  the  size  of  the  measuring- 
tubes  has  to  be  increased,  rendering  the  comparison  of 
color  more  difficult. 

The  use  of  the  color-test  is  limited  by  the  fact  that 
certain  treatments  which  the  steel  may  have  undergone 
change  the  condition  of  the  carbon ;  thus  a  steel  shows 
less  carbon  by  color  when  hardened  than  when  unhard- 
ened,  and  more  when  annealed  than  when  unannealed ; 
it  is  therefore  important  to  use  standards  that  have 
undergone  approximately  the  same  physical  treatment 
as  the  samples  operated  upon.  When  this  is  not 
practicable,  combustion  must  be  resorted  to.  There 
are  many  devices  in  the  market  for  facilitating  the 
color-test,  called  chromometers,  etc.  None  of  them 
offer  any  special  advantage.  The  method  of  having 
standard  solutions  with  so-called  permanent  colors,  in 
stead  of  dissolving  a  standard  with  every  set  of  carbon 
determinations,  is  entirely  untrustworthy.  As  to  the 
quantity  of  acid  used,  it  may  be  modified  a  little,  so  that 
somewhat  more  be  used  for  very  high  carbons  and  less 
for  low  carbons.  Care  must  be  taken,  however,  that  in 
each  set  of  determinations  the  same  quantity  be  used. 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  23 

It  is  of  course  not  necessary  to  dilute  the  standard 
so  as  to  correspond  exactly  to  .0001  gram  per  cubic  cen- 
timetre. The  above  .84  standard  diluted  to  20  cubic 
centimetres  would  correspond  to  .000084  grams  per 
cubic  centimetre,  and  the  carbon  in  our  sample  would 
have  been  found  say  between  17  cubic  centimetres  and 
1 8  cubic  centimetres,  consequently  between  .71  per  cent 
and  .75  per  cent  (V-  X  .084  and  -1/-  X  .084). 

e.  Determination  of  Phosphorus.  Five  grams  of 
drillings  are  dissolved  in  a  beaker  (No.  5  Griffin's  wide 
lipped)  in  nitric  acid,  1.20  specific  gravity.  The  solution 
is  then  evaporated  with  excess  of  strong  hydrochloric 
acid  by  rapid  boiling  on  a  large  iron  plate  heated  by 
one  or  more  Fletcher's  solid  flame  burners.  Water-baths 
and  sand-baths  are  entirely  unnecessary  for  the  methods 
of  analysis  described  in  this  book.  The  plate  is  so 
heated  that  the  heat  gradually  decreases  from  the  cen- 
tre towards  the  edges.  The  hottest  part  ought  to  be 
rather  above  than  below  300°  C.  The  plate  is  a  very 
simple,  yet  a  most  important  and  useful  apparatus  in  an 
iron  laboratory.  The  evaporation  is  continued  on  the 
hottest  part  of  the  plate  until  signs  of  spattering  are 
noticed.  The  beaker,  or  beakers,  are  then  moved  to  a 
less  hot  part  of  the  plate.  When  the  tendency  to  spat- 
ter has  ceased  the  beakers  are  moved  back  to  the  hottest 
part  of  the  plate  and  left  there  for  at  least  half  an  hour. 
This  heating  is  necessary  in  order  to  completely  oxidize 
and  decompose  the  last  traces  of  iron  phosphide,  which 
otherwise  would  remain  insoluble  with  the  silica.  The 


24  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

presence  of  hydrochloric  acid  lessens  the  tendency  to 
spatter,  which  is  always  less  in  high  carbon  steels  than 
in  low  carbon  steels.  The  beakers  are  now  slowly- 
cooled  and  strong  hydrochloric  acid  added  in  excess. 
The  acid  is  at  once  brought  to  a  boil,  which  effects  a 
solution  of  the  residue,  and  the  boiling  is  continued 
until  only  a  small  bulk  remains,  with  the  silica  sticking 
to  the  sides  of  the  beaker.  This  boiling  serves  two  pur- 
poses: firstly,  to  convert  any  pyrophosphoric  acid  (H4 
P2  O7),  which  may  have  been  formed  on  the  strong  heat- 
ing, into  orthophosphoric  acid  (H3  PO4) ;  secondly,  to 
concentrate  the  solution,  so  as  to  render  filtration  easier 
and  remove  excess  of  hydrochloric  acid,  which  would 
otherwise  interfere  with  the  precipitation  of  phosphorus 
by  means  of  molybdic  acid.  Hot  water  is  added  to  the 
concentrated  solution  and  the  silica  filtered  off  on  a 
four-inch  Swedish  filter-paper.  It  is  well  to  collect 
the  filtrate  in  a  conical  assay-flask.  The  silica  must  be 
well  rubbed  off  from  the  sides  of  the  beaker  by  means 
of  a  piece  of  rubber-tubing  attached  to  the  end  of  a 
glass  rod.  The  washing  of  this  silica  is  done  by  means 
of  dilute  hydrochloric  acid  and  plenty  of  hot  water. 
The  silica  thus  obtained  will  in  most  cases  burn  per- 
fectly white  and  can  be  used  for  the  determination  of 
silicon.  The  burnt  silica  contains  467,  or  T7^,  of  silicon. 
The  phosphorus  in  the  filtrate  is  precipitated  as  the 
yellow  phosphomolybdate  of  ammonia.  For  this  pre- 
cipitation is  used  a  solution  of  about  one  part  by  weight 
of  molybdic  acid  in  four  weights  of  ammonia,  .96  spe- 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS.  25 

cific  gravity,  and  fifteen  parts  of  nitric  acid,  1.20  specific 
gravity.  The  molybdic  acid  is  first  dissolved  in  the 
ammonia  and  this  solution  slowly  poured  into  the 
nitric  acid,  which  must  be  shaken  constantly  in  order 
to  prevent  the  separation  of  molybdic  acid,  which  re- 
dissolves  with  difficulty.  After  a  few  days'  standing  the 
solution  may  be  siphoned  off  clear.  Fifty  to  one  hun- 
dred cubic  centimetres  of  this  molybdic  acid  solution 
are  used  for  each  phosphorus  determination.  To  pre- 
cipitate the  phosphomolybdate  of  ammonia  in  the 
filtrate  from  the  silica,  sufficient  ammonia  (.96  specific 
gravity)  is  added  to  nearly  neutralize  the  solution.  The 
fifty  cubic  centimetres  of  molybdic  acid  solution  are 
then  added  and  the  flask  well  shaken.  If  the  yellow 
precipitate  is  slow  in  coming  down,  a  little  more  am- 
monia may  be  added.  If  too  much  ammonia  is  added, 
a  little  strong  nitric  acid  must  be  introduced  to  re- 
dissolve  the  iron  precipitate.  As  a  rule  the  yellow 
precipitate  comes  down  very  quickly.  By  neutralizing 
the  solution  before  adding  the  molybdic  acid  as  de- 
scribed, the  yellow  precipitate  becomes  granular  and 
easy  to  filter.  When  precipitated  in  any  other  way  it 
has  a  great  tendency  to  pass  through  and  creep  over 
the  edges  of  the  filter.  The  yellow  precipitate  is 
allowed  to  settle  over  night  at  about  40°  C,  or  during 
a  few  hours  at  80°  C.  After  settling,  the  clear  super- 
natant liquid  is  siphoned  off  and  thrown  away  (or 
kept  for  reclaiming  the  molybdic  acid).  The  yellow 
precipitate  is  filtered  off  on  a  four-inch  Swedish  filter 


26  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  good  quality  and  washed  with  copious  quantities  of 
the  above-mentioned  molybdic  acid  solution,  diluted 
with  an  equal  volume  of  water.  About  300  cubic 
centimetres  of  washings  are  not  too  much  to  insure 
the  complete  removal  of  the  last  traces  of  iron.  The 
yellow  precipitate  is  then  treated  on  the  filter  with  a 
little  hot  ammonia,  .96  specific  gravity,  and  the  filtrate 
allowed  to  run  back  into  the  assay-flask  in  which  the 
precipitation  was  made.  When  all  is  dissolved,  the 
ammoniacal  solution  is  thrown  on  to  the  same  filter 
again,  but  now  to  run  into  a  100  cubic  centimetre 
beaker.  The  filter  is  washed  with  a  little  cold  water, 
so  that  the  bulk  of  the  ammoniacal  solution  will  be 
from  20  to  30  cubic  centimetres.  To  the  filtrate  thus 
obtained  are  added  about  3  cubic  centimetres  of  hydro- 
chloric acid,  1. 1 2  specific  gravity,  and  a  few  drops  of 
ammonia  to  redissolve  any  yellow  salt  that  may  have 
separated.  Then  add  10  cubic  centimetres  of  magnesia 
mixture  and  shake  until  the  white  crystalline  phosphate 

of  magnesia  and  ammonia  appears  ( N^|  j-  PO4  +  6  H2oV 

About  6  cubic  centimetres  of  ammonia,  .96  specific 
gravity,  are  then  added.  If  a  good  shaking  now  be 
applied  the  precipitate  will  be  down  completely  in  two 
hours ;  if,  however,  time  is  not  available  for  shaking, 
the  beaker  must  be  left  standing  for  at  least  six  hours 
before  filtering.  With  very  vigorous  shaking  the  pre- 
cipitate can  be  brought  down  in  half  an  hour.  The 
white  precipitate  is  filtered  on  to  a  two-inch  Swedish 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  27 

filter-paper  and  washed  with  ammonia,  .96  specific 
gravity,  diluted  with  three  times  its  volume  of  water. 
About  80  cubic  centimetres  of  this  mixture  is  suf- 
ficient for  washing  the  precipitate.  It  is  advisable  not 
to  use  more  than  80  cubic  centimetres  of  wash-water, 
as  the  same  has  a  slightly  solvent  action  on  the  pre- 
cipitate. The  white  precipitate  must  be  rubbed  loose 
from  the  sides  of  the  beaker,  like  the  silica,  with  rubber 
tubing  on  a  glass  rod. 

The  magnesia  mixture  is  prepared  by  dissolving  no 
grams  of  magnesium  chloride  together  with  280  grams 
of  ammonium  chloride  in  1,300  cubic  centimetres  of 
water  and  adding  700  cubic  centimetres  of  ammonia, 
.96  specific  gravity,  to  the  solution.  After  a  few  days' 
standing  the  solution  can  be  siphoned  off  clear  from 
the  sediment.  The  chloride  of  ammonium  prevents 
the  precipitation  of  magnesium  hydrate.  The  following 
formulas  show  how  this  occurs  :  — 

2  Mg  Cl,  +  2  NH8  +  2  H20   =  Cl4  +  Mg  H2°2'          and 


Mg  H2O2  +  4  NH4  Cl   =    ,$!§  ,  I  C14  +  2  NH8  +  2  H2O. 

(n  tt4;2  ) 

The  filter  with  the  well-washed  white  precipitate  is 
put,  while  still  wet,  into  a  weighed  platinum  crucible  and 
ignited.  The  ignition  is  best  conducted  by  keeping 
the  crucible  in  an  upright  position  and  placing  the  lid 
in  a  slanting  position  in  the  same.  At  first  only  the 
top  or  oxidizing  part  of  the  burner-flame  is  allowed  to 
strike  the  crucible.  When  all  the  filter-paper  is  burnt 


28  NOTES    ON    THE    CHEMISTRY    OF   IRON. 

off  more  of  the  flame  may  be  brought  into  contact  with 
the  crucible.  Should  some  carbon  still  refuse  to  burn 
out,  moisten  with  a  little  nitric  acid  and  ignite  again. 
The  ignited  precipitate  is  pyrophosphate  of  magnesia, 
Mg2  P2  O7,  containing  very  nearly  28  per  cent  of  phos- 
phorus. Care  must  be  taken  that  the  filter  does  not 
leave  any  appreciable  amount  of  ash.  This  can  be 
insured  by  washing  every  filter  out  with  hydrochloric 
acid  before  using  it. 

The  yellow  precipitate,  when  dried  at  95°  to  140° 
C,  contains  1.63  per  cent  of  phosphorus  and  can  be 
used  for  a  direct  phosphorus  determination.  It  must 
then  be  washed  with  water  containing  i  per  cent  by 
volume  of  nitric  acid,  1.20  specific  gravity,  instead  of 
with  the  dilute  molybdic  acid  solution.  After  drying 
it  is  transferred  from  the  filter,  by  shaking  and  brush- 
ing, into  a  weighed  watch-glass,  or  some  other  suitable 
vessel,  and  weighed.  When  much  phosphorus  is  pres- 
ent this  method  can  be  used  with  great  accuracy,  but 
when  little  the  risk  of  loss  in  brushing  off  is  too  great. 
Weighed  filters  have  then  to  be  used.  The  magnesia 
method  is,  however,  undoubtedly  the  best  of  the  two 
methods  in  general  working. 

When  precipitating  phosphorus  with  the  molybdic 
acid  solution  above  described,  it  should  be  borne  in 
mind  that  100  cubic  centimetres  of  the  said  solution 
are  required  for  the  complete  precipitation  of  .1  gram  of 
phosphoric  anhydride  (P2  O5),  containing  .044  gram  of 
phosphorus.  Ten  cubic  centimetres  of  the  magnesia 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  29 

mixture    are    required   for  the  same   quantity  of   phos- 
phorus. 

f.  Determination  of  Manganese.  Five  grams  of 
sample  are  dissolved  in  about  150  cubic  centimetres 
of  dilute  nitric  acid,  1.20  specific  gravity.  The  solution 
is  then  boiled  on  the  plate  (see  p.  23)  with  the  addition 
of  strong  nitric  acid,  1.42  specific  gravity,  until  the  bulk 
is  about  100  cubic  centimetres.  If  the  silicon  in  the 
sample  is  much  higher  than  .2  per  cent  a  clogging  of 
the  filter  in  the  subsequent  filtration  may  occur.  In 
such  cases  it  is  therefore  best  to  dissolve  the  sample  in 
dilute  hydrochloric  acid  and  evaporate  to  gentle  dry- 
ness.  The  dry  mass  is  then  dissolved  in  strong  nitric 
acid  and  boiled  to  complete  destruction  of  the  hydro- 
chloric acid.  To  the  solution  evaporated  to  100  cubic 
centimetres  small  crystals  of  chlorate  of  potash  are 
gradually  added.  Yellow  and  green  fumes  come  off; 
and,  after  boiling  has  been  continued  for  a  while,  all 
the  manganese  separates  as  dioxide  (Mn  O2),  insoluble 
in  the  strong  nitric  acid.  The  reactions  may  be  con- 
sidered to  be, — 

2  Mn  O  +  N2  O5   =   2  Mn  O2  +  N2  O8,         and 
N203  +  C1205   -   N205  +  C1203. 

The  chlorous  acid  gas  (C12  O3)  is  very  explosive. 
By  using  a  smaller  bulk  than  100  cubic  centimetres 
violent  explosions  may  occur,  throwing  the  lid  off  the 
beaker.  On  the  other  hand  it  is  not  good  to  use  a 
much  larger  bulk  than  100  cubic  centimetres,  as  the 


30  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

solution  foams  rather  violently  on  addition  of  the 
chlorate  of  potash.  Most  likely  the  reactions  are  far 
more  complicated  than  as  above  given,  the  higher  ox- 
ides of  manganese  first  forming  and  the  dioxide  of 
manganese  separating  on  boiling. 

After  boiling  the  precipitated  manganese  dioxide  for 
a  few  minutes  some  cold  strong  nitric  acid  is  added 
and  the  precipitate  filtered  off  on  an  ordinary  asbestos 
filter  in  a  glass  tube  by  means  of  the  suction-pump. 
Care  must  be  taken  that  the  nitric  acid  here  used  con- 
tain no  nitrous  acid  (N2  O3),  the  presence  of  which  would 
cause  a  reduction  of  the  manganese  dioxide  to  lower 
oxides.  A  yellow  color  indicates  the  presence  of  nitrous 
acid  in  the  nitric  acid.  Bottles  that  have  been  contami- 
nated with  nitrous  acid  and  nitric  oxide  gas  (N2  O4)  are 
easily  cleaned  by  shaking  them  with  water,  which  dis- 
solves said  impurities.  The  manganese  dioxide  is 
washed  on  the  filter  twice  with  cold  strong  nitric  acid 
and  four  times  with  cold  water.  After  washing,  the  pre- 
cipitate together  with  the  asbestos  is  blown  back  into 
the  beaker  in  which  the  precipitation  was  originally 
made.  The  manganese  may  now  be  determined  either 
gravimetrically  or  volumetrically  with  equal  accuracy. 
The  latter  method,  on  account  of  its  rapidity,  is  always 
preferable  where  large  numbers  of  determinations  are 
constantly  made. 

(a)  Gravimetric  Determination.  Boil  the  precipitated 
dioxide  with  hydrochloric  acid  until  all  chlorine  is 
driven  off,  the  manganese  being  thereby  converted  into 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  3! 

the  proto-salt  (Mn  O).  Dilute  with  water  and  filter  off 
the  asbestos.  Add  a  little  concentrated  acetic  acid  to 
the  hot  filtrate  and  neutralize  with  ammonia,  .88  specific 
gravity,  until  the  solution  barely  smells  of  acetic  acid. 
Boil,  and  allow  the  precipitated  basic  acetate  of  iron 
(a  little  iron  always  accompanies  the  Mn  O2)  to  settle. 
If  the  smell  of  acetic  acid  now  seem  rather  strong 
add  a  little  dilute  ammonia.  Then  filter  and  wash  well 
with  hot  water.  If  the  precipitated  oxide  of  iron  looks 
reddish  all  over4  it  may  be  considered  as  free  from 
manganese ;  but  if  brownish  flakes  appear  floating  on 
the  surface  during  the  filtering,  the  presence  of  man- 
ganese oxides  is  indicated,  and  it  becomes  necessary  to 
redissolve  the  precipitate  by  boiling  with  hydrochloric 
acid  and  to  repeat  the  basic  acetate  precipitation  as 
above  directed  in  order  to  insure  the  complete  separa- 
tion of  the  iron  from  the  manganese.  To  the  filtrate, 
or  filtrates,  from  the  above  basic  acetate  precipitation 
an  excess  of  the  strong  ammonia  is  added  and  then, 
with  vigorous  stirring,  a  few  cubic  centimetres  of  bro- 
mine, by  which  the  hydrates  of  the  higher  oxides  of 
manganese  are  precipitated.  Heat  gradually  to  boiling, 
allow  to  settle,  filter,  ignite  in  a  platinum  crucible  and 
weigh  as  Mn3  O4,  containing  72.08  per  cent  of  Mn.  The 
ignition  must  be  either  very  long  and  protracted  over  an 
ordinary  Bunsen's  burner  or  short  over  the  blast-lamp. 
The  washing  of  the  manganese  precipitate  is  easily 
accomplished  by  means  of  hot  water,  there  being  only 
volatile  ammoniacal  salts  present  and  no  fixed  alkali. 


32  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

(/3)  Volumetric  Determination.  The  volumetric  de- 
termination of  the  manganese  in  the  above-described 
dioxide  precipitate,  in  which  all  the  Mn  exists  as  di- 
oxide, consists  in  general  in  dissolving  the  dioxide  in 
a  measured  amount  of  a  standard  acid  solution  of 
ferrous  sulphate,  by  which  the  Mn  O2  is  at  once  re- 
duced to  Mn  O,  an  excess  of  ferrous  sulphate  remaining. 
The  amount  of  this  excess  is  then  determined  with  a 
standard  solution  of  bichromate  of  potash,  from  which 
data  the  amount  of  manganese  dioxide  dissolved  in 
and  reduced  by  the  acid  ferrous  sulphate  can  be  esti- 
mated. For  the  method  as  above  mentioned  is  required 
a  standard  solution  of  ferrous  sulphate,  a  standard 
solution  of  bichromate  of  potash  and  a  solution  of 
ferricyanide  of  potash  (K6  CN12  Fe2).  The  last-named 
solution  is  prepared  separately  for  every  set  of  deter- 
minations. The  ferrous  sulphate  solution  is  prepared 
by  dissolving  20  grams  of  ferrous  sulphate  (Fe  SO4  -(- 
7  H2  O,  containing  one-fifth  part  of  iron)  in  1,600  cubic 
centimetres  of  water  and  400  cubic  centimetres  of  sul- 
phuric acid  of  about  1.5  specific  gravity.  This  solution, 
when  kept  in  darkened  two-liter  bottles  with  ground 
stoppers,  will  not  perceptibly  change  in  strength  (i.e., 
will  not  be  oxidized)  even  when  kept  for  a  long  time. 
The  bichromate  solution  is  prepared  by  dissolving 
about  10  grams  of  the  salt  in  i  liter  of  water.  One 
cubic  centimetre  of  this  solution  will  very  nearly  ox- 
idize such  an  amount  of  the  ferrous  sulphate  to  ferric 
sulphate  as  would  contain  .on  of  a  gram  of  iron, 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  33 

as  per  the  following  formulas  of  combining  propor- 
tions :  — 

6  Fe  SO4  +  K2  Cr2  O7  +  7  H2  SO4   =   3  Fe2  3  SO4  +  K2  SO4  + 
Cr2  3  SO4  +  7  H2O. 

.  One  hundred  cubic  centimetres  of  the  ferrous  sul- 
phate solution,  of  the  strength  as  above  directed,  will 
correspond  to  18.1  cubic  centimetres  of  the  above  bi- 
chromate solution.  The  ferrous  sulphate  solution  must 
be  checked  for  strength  with  every  set  of  determina- 
tions, if  the  intervals  of  time  between  such  determina- 
tions is  considerable.  The  standardizing  of  the  bichro- 
mate solution  may  be  effected  by  making  therewith 
three  separate  determinations  of  iron  in  three  carefully 
weighed  amounts  —  from  one  to  two  grams  each  —  of 

ammonio-ferro- sulphate    (^p2}*  SO4  +  6  H2oY  which 

salt  can  always  be  obtained  pure,  and  then  contains 
one-seventh  part  of  iron.  Pure  iron  wire  may  also  be 
used  for  standardizing  the  bichromate.  The  bichro- 
mate solution  is  made  up  in  large  quantities,  as  it  will 
retain  its  strength  unchanged  for  years.  It  should  be 
kept  in  a  large  bottle  on  a  high  shelf,  so  arranged 
that  the  solution  can  be  conveniently  run  into  a  100 
cubic  centimetre  Mohr's  burette,  with  Erdmann's  float, 
through  a  tube  attached  to  the  lower  part  of  the  bottle. 
A  porcelain  dish  of  at  least  one  liter  capacity  is 
placed  under  the  burette.  This  dish  receives  the  solu- 
tion to  be  titrated.  In  a  small  beaker  some  crystals 
of  ferricyanide  of  potash  are  dissolved  in  water.  There 


34  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

is  no  need  of  weighing  out  an  exact  quantity;  but 
enough  should  be  added  to  give  the  solution  a  bright 
yellow  color,  not  a  greenish  or  pale  yellow  tint.  Drops 
of  this  solution  are  placed  in  the  cavities  of  a  porcelain 
test-plate,  such  as  is  used  by  artists  for  water-colors.  By 
conveying  drops  of  the  solution  in  the  dish  to  be  titrated 
on  a  glass-rod,  and  mixing  them  with  the  yellow  drops 
of  the  ferricyanide,  we  notice  how  the  resulting  blue 
color,  on  addition  of  bichromate  to  the  solution  in 
the  dish,  becomes  first  lighter  and  then  greenish ;  and 
finally,  after  the  addition  of  a  last  one-tenth  of  a  cubic 
centimetre  of  bichromate,  how  the  drops  show  a  de- 
cided brownish  tint.  This  brownish  tint  indicates  that 
the  last  trace  of  protoxide  of  iron  has  been  converted 
into  peroxide. 

The  determination  of  the  manganese  is  now  easily 
understood.  Add  from  a  pipette  100  cubic  centimetres 
of  the  standard  ferrous  sulphate  solution  to  the  Mn  O2 
precipitate,  which  has  been  blown  back  into  the  beaker 
as  described,  and  shake  well  until  all  the  manganese  is 
decomposed  and  dissolved.  Then  determine  by  titra- 
tion  in  the  dish  how  much  iron  has  been  left  unoxidized 
by  the  manganese  dioxide.  The  reaction  is  — 

Mn  O2  +  2  Fe  O  =   Fe2  O3  +  Mn  O. 

In  the  above  formula  one  part  of  iron  corresponds  to 
.491  part  of  manganese.  A  table  may  thus  be  prepared 
and  can  be  pasted  on  to  the  bottle  containing  the  bi- 
chromate solution  as  follows :  — 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  35 

i  cubic  centimetre  bichromate   =    .on  gram  Fe. 
i  cubic  centimetre  bichromate    =    .0054  gram  Mn. 

Or,  when  5  grams  of  sample  have  been  used,  — 

zJiaAA   =    .00108  grams  Mn 

=   .108  per  cent  of  Mn  in  sample. 

Suppose  ioo  cubic  centimetres  of  the  ferrous  sul- 
phate correspond  to  18.1  cubic  centimetres  of  the  bi- 
chromate and,  further,  that  15.1  cubic  centimetres  of  the 
latter  are  found,  by  titration,  to  be  required  for  oxidizing 
the  ferrous  sulphate  left  unoxidized  by  the  manganese 
dioxide,  then  we  have  18.1  —  15.1  =  3  cubic  centi- 
metres of  bichromate,  corresponding  to  the  iron  that 
has  been  oxidized  in  the  ferrous  sulphate  by  the  manga- 
nese dioxide.  Having  used  five  grams  of  sample,  we 
find  direct  from  the  above  table  3  X  .108  =  .324  per 
cent  of  manganese.  The  top  of  the  burette  should  be 
kept  closed  by  a  piece  of  cotton,  to  prevent  the  entrance 
of  organic  matter  which  would  cause  a  slow  decom- 
position of  the  bichromate  when  exposed  to  strong 
sunlight.  The  burette  must  always  be  kept  filled  to 
the  top. 

g.  Determination  of  Silicon.  The  silica  obtained 
in  the  phosphorus  determination  (see  p.  24)  is  apt  to 
contain  some  impurities.  It  is  therefore  advisable  to 
use  the  following  special  method  which  has  a  more 
general  application  and  which  gives  a  pure  silica  in 
the  largest  number  of  cases. 

Five  grams  of  sample  are  dissolved  in  such  a  quantity 


36  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  dilute  sulphuric  acid  that  on  each  gram  of  drillings 
come  2  cubic  centimetres  of  the  strong  acid.  When  all 
is  dissolved  strong  nitric  acid  is  cautiously  added  until 
no  more  effervescence  occurs.  The  solution  is  then 
boiled  down  on  the  plate  until  white  fumes  appear ;  the 
dry  mass  is  moistened  with  a  little  hydrochloric  acid 
and  then  dissolved  in  a  small  excess  of  boiling  water. 
When  solution  has  been  effected,  the  silica  is  filtered 
off,  washed  with  dilute  hydrochloric  acid  and  hot  water, 
ignited  and  weighed  (see  p.  24). 

h.  Determination  of  Sulphur,  (a)  Bromine  Method. 
Ten  grams  of  sample  are  weighed  out  and  put  into 
the  half-liter  flask  A  (Fig.  VII.)  with  long  neck.  The 
flask  is  connected  with  the  absorption-bulbs  B  contain- 
ing hydrochloric  acid,  1.12  specific  gravity,  and  about 
5  cubic  centimetres  of  bromine.  The  wide  tube  C 
causes  the  vapor  to  condense  and  flow  back  into  the 
flask  A  during  boiling.  The  bulbs  B  connect  with  a 
long  glass  tube  by  which  the  bromine  fumes  can  be 
carried  off  through  a  hole  in  a  window,  or,  better  still, 
through  a  flue  with  strong  draught.  The  connections 
being  made,  200  cubic  centimetres  of  boiling  water  are 
run  in  through  the  thistle-tube  T.  The  air  is  thus 
completely  driven  out  of  the  flask.  Two  hundred  cubic 
centimetres  of  strong  hydrochloric  acid  are  then  added. 
When  the  gas  begins  to  run  rather  slowly  through  B 
heat  is  applied  until  boiling  gradually  ensues.  When 
the  steel  is  completely  dissolved  the  apparatus  is  dis- 
connected and  the  contents  of  the  bulbs  B  rinsed  out 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS. 


37 


into  a  beaker  of  100  cubic  centimetres  capacity,  into 
which  a  few  cubic  centimetres  of  a  concentrated  solu- 
tion of  chloride  of  barium  (100  grams  of  Ba  C12  in  i 
liter  of  water)  have  been  previously  introduced.  Heat 
is  then  applied  to  the  beaker  on  the  hot  iron  plate  until 
the  bromine  is  completely  driven  off  and  the  sulphate 


4  in.     D 


FIG.  VII. 

of  barium  has  settled  nicely  to  the  bottom.  The  barium 
sulphate  is  then  filtered  off  on  a  small  double  filter, 
washed  with  hot  water  and  finally  ignited  and  weighed. 
The  filter  should  always  be  put  into  the  crucible  whilst 
still  wet.  The  ignited  barium  sulphate  contains  13.72 
per  cent  of  sulphur.  A  perfectly  pure  barium  sulphate 
is  obtained  by  this  method,  there  being  no  bases  present 
by  which  it  can  be  contaminated.  During  the  passage 


38  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  the  gas  through  the  bulbs  B,  oily  drops  of  propyl- 
bromide,  etc.,  are  formed,  which,  however,  disappear  on 
heating.  The  reaction,  by  means  of  which  the  sulphur 
is  retained  in  the  bromine  solution,  is  as  follows :  H2  S 
+  4  H2  O  +  8  Br  =  H2  SO4  -f  8  H  Br.  For  making 
many  determinations  in  succession  it  is  convenient  to 
have  a  large  number  of  bulbs  filled  and  suspended  in 
a  box  of  suitable  form,  as  well  as  many  flasks.  The 
flasks  must  be  perfectly  dry  before  putting  the  drillings 
into  the  same. 

(b)  "  Aqua  Regia  "  Method.  If  the  iron  or  steel  con- 
tain much  copper,  —  say  more  than  one-fourth  of  one 
per  cent,  —  or  other  elements  that  are  precipitated  by 
H2  S  in  acid  solution,  the  bromine  method  is  apt  to 
give  too  low  results.  If  the  samples  be  very  coarse  the 
solution  in  H  Cl  proceeds  too  slowly  and  the  bromine 
method  becomes  difficult  to  manage.  In  these  cases 
the  following  method  can  best  be  used. 

Five  grams  of  sample  are  treated  in  exactly  the  same 
way  as  for  phosphorus  determination,  care  being  taken 
to  have  all  reagents  perfectly  free  from  sulphur  and 
also  taking  the  precaution  to  add  a  little  sodium  car- 
bonate before  drying  on  the  iron  plate.  If  this  pre- 
caution be  omitted  some  sulphuric  acid  may  be  lost 
through  volatilization.  To  the  filtrate  from  the  silica 
—  which  should  amount  to  at  least  300  cubic  centime- 
tres—  a  few  cubic  centimetres  of  Ba  C12  solution  are 
added.  After  standing  one  night  at  the  temperature  of 
the  room  the  sulphate  of  barium  is  completely  precipi- 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  39 

tated  and  can  be  filtered  off,  washed  thoroughly  in  the 
beaker  with  strong  H  Cl  and  on  the  filter  with  dilute 
H  Cl  and  hot  water,  ignited  (compare  p.  36),  and 
weighed. 

i.  Determination  of  Copper.  Five  grams  of  sam- 
ple are  dissolved  in  a  mixture  of  10  cubic  centimetres 
of  strong  sulphuric  acid  and  150  cubic  centimetres  of 
water.  Heat  to  full  boiling  and  add,  with  constant 
stirring,  2  cubic  centimetres  of  a  concentrated  solution 
of  the  thiosulphate  —  formerly  known  as  "  hyposulphite  " 
—  of  soda  (Na2  S2  O3  -j-  5  H2  O).  The  thiosulphate 
solution  is  obtained  of  proper  strength  by  dissolving 
eighteen  parts  of  the  salt  in  twenty  parts  of  water.  The 
copper  is  precipitated  as  subsulphide  (Cu2  S)  together 
with  free  sulphur.  This  subsulphide  does  not  oxidize 
in  the  air  during  washing,  etc.,  which  is  of  great  advan- 
tage. It  is  filtered  off  and  washed  somewhat  with  hot 
water.  The  whole  precipitate,  including  carbon  residue, 
free  sulphur,  iron,  etc.,  is  washed  back  into  the  beaker 
in  which  the  precipitation  was  made,  dissolved  by  boil- 
ing with  some  aqua  regia  and  evaporated  with  sul- 
phuric acid  to  complete  expulsion  of  H  Cl  and  H  N 
Og.  Dilute  with  cold  water  and  precipitate  the  iron 
present  with  excess  of  strong  ammonia  at  a  boiling 
heat.  Filter  off  the  precipitate  and  wash  with  ammo- 
niacal  water.  If  any  appreciable  amount  of  copper  is 
present,  the  filtrate  will  appear  blue  or  bluish-green. 
Acidify  with  sulphuric  acid  in  slight  excess,  heat  to  boil- 
ing and  precipitate  the  copper,  now  pure,  with  a  few 


40  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

drops  of  thiosulphate.  Filter  off,  put  the  precipitate 
whilst  wet  in  a  weighed  porcelain  crucible  and  ignite 
strongly.  Weigh  as  cupric  oxide  (Cu  O),  containing 
79.8  per  cent  of  copper. 

In  the  method  above  described  the  iron  was  origi- 
nally present  as  Fe  O.  If,  however,  copper  is  to  be 
determined  in  a  solution  containing  Fe2  O3,  much  more 
thiosulphate  solution  is  required,  as  the  Cu2  S  does  not 
come  down  until  all  the  iron  has  been  completely  re- 
duced, as  per  formula :  — 

Fe2  3  SO4  +  2  Na2  S2  O3   =   2  Fe  SO4  +  Na2  S4  O6  +  Na2  SO4. 

(Sodium  tetrathionate.) 

Thus  if  in  a  solution  of  5  grams  of  borings  all  the  iron 
exists  as  Fe2  O3,  about  30  cubic  centimetres  of  the  thio- 
sulphate would  be  required.  In  such  cases  it  is  easy  to 
notice,  with  sufficient  accuracy  for  the  purpose,  the 
point  when  enough  thiosulphate  has  been  added.  As 
long  as  there  is  any  peroxide  left,  a  black  color  appears 
and  again  disappears  after  each  addition  of  thiosulphate. 
Finally  the  color  of  the  solution  changes  to  a  light 
green.  This  is  the  point  when  enough  has  been  added. 
A  little  sulphur  then  begins  to  separate  and,  if  any 
copper  be  present,  a  black  precipitate  soon  appears  on 
continued  boiling.  Hydrochloric  acid  must  be  absent 
in  this  operation  as  it  seems  to  be  impossible  to  effect 
complete  precipitation  of  Cu  in  its  presence.  Nitric 
acid  retards  the  precipitation  in  the  same  way  as  Fe2 
O3,  inasmuch  as  the  same  must  be  reduced  before  the 
Cu  is  precipitated.  If  great  excess  of  sulphuric  acid 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS.  4! 

and  thiosulphate  be  used  the  copper  will  not  be  com- 
pletely precipitated.  Two  cubic  centimetres  of  sulphu- 
ric acid  solution,  1.83  specific  gravity,  are  required  to 
decompose  5  cubic  centimetres  of  the  above  thiosul- 
phate solution  and  1.05  cubic  centimetres  of  the  same 
strong  sulphuric  acid  are  required  to  dissolve  i  gram  of 
iron.  One-tenth  gram  of  copper,  contained  in  solution 
as  sulphate  and  dissolved  in  50  cubic  centimetres  of 
water,  is  completely  precipitated  by  i  cubic  centimetre 
of  the  thiosulphate  solution. 

The  reaction  according  to  which  the  Cu2  S  is 
obtained  is  unknown.  It  is  considered  that  at  first 
thiosulphate  of  copper  is  formed  which,  on  boiling, 
decomposes  into  Cu2  S  and  into  a  sulphuric  acid  of 
unknown  composition. 

It  must  be  remembered  that  many  other  metals  — 
such  as  arsenic,  antimony,  lead,  tin,  bismuth,  etc.  —  are 
also  precipitated  by  the  thiosulphate  as  sulphides.  In 
wrought  iron  and  steel,  however,  these  metals  do  not 
often  occur  in  sufficient  quantity  to  cause  any  error. 

j.  Determination  of  Slag  and  Oxide  of  Iron. 
Slag  and  oxides  of  iron  usually  occur  in  wrought  iron 
in  considerable  quantities.  Steels  are,  as  a  rule,  com- 
paratively free  from  the  same.  When,  however,  these 
impurities  do  occur  in  steels  in  unusual  quantities,  the 
quality  of  the  metal  is  seriously  affected  thereby  and 
their  determination  becomes  important.  It  has  been 
found  very  difficult  to  make  such  determinations  with 
accuracy  and,  although  it  is  believed  that  the  following 


42  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

method  is  superior  to  those  usually  proposed,  it  must 
be  borne  in  mind  that  it  does  not  give  results  which  can 
be  compared  in  accuracy  with  those  obtained  by  the 
methods  already  given  for  the  determination  of  other 
impurities. 

Five  grams  of  drillings  are  treated  with  250  cubic 
centimetres  of  a  ferric  chloride  solution  containing 
about  i  part  of  crystals  of  ferric  chloride  to  1.5  part  of 
water.  Care  must  be  taken  to  use  chemically  pure 
ferric  chloride,  and  the  crystals  should  smell  somewhat 
of  chlorine.  The  water  should  be  previously  freed 
from  air  by  boiling  and  subsequent  cooling  to  the 
ordinary  temperature.  A  flask  similar  to  those  used  in 
carbon  determination  (p.  7)  is  well  suited  for  the  decom- 
position, which  takes  place  as  per  formula :  — 

Fe2  Cl.  +  Fe   =  3  Fe  C12. 

The  residue  contains  all  the  slags  and  oxides  of  iron, 
some  free  silica  and  silicon  and,  further,  various  com- 
pounds of  iron  with  other  bodies,  such  as,  principally, 
phosphorus,  sulphur,  arsenic  and  carbon.  Nearly  all 
the  carbon  is  left  with  the  residue. 

It  should  be  borne  in  mind  that  wrought  irons  and 
steels  are  produced  by  oxidizing  processes,  whilst  pig- 
iron  is  produced  by  a  reducing  process.  The  former, 
during  their  manufacture,  are,  therefore,  apt  to  lose 
various  ingredients  that  have  greater  affinity  for  oxygen 
than  has  iron,  —  such  as  silicon,  manganese,  titanium, 
chromium,  vanadium  etc.,  —  whilst  the  latter  may  take 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  43 

up  any  number  of  such  elements.  Copper,  cobalt  and 
nickel  are  more  easily  reduced  from  their  oxygen  com- 
pounds than  iron,  and  therefore  generally  remain  with 
the  iron  through  all  stages  of  manufacture.  From  the 
above  it  follows  that  the  residue  obtained  by  the  treat- 
ment of  wrought  iron  and  steel  with  ferric  chloride 
contains,  as  a  rule,  fewer  compounds  of  iron  with  other 
elements  than  when  pig-iron  is  so  treated.  Sometimes, 
however,  such  compounds  do  occur.  The  author  found 
lately  in  some  steel-blooms  made  by  the  "  basic "  pro- 
cess a  black  compound,  when  searching  for  silicon 
according  to  the  methods  described.  This  black  com- 
pound resisted  all  acids  and  even  the  strong  heating 
in  the  determination  of  phosphorus  failed  to  decom- 
pose it.  Fusion  with  alkaline  carbonates  was  necessary 
to  effect  decomposition.  It  was  present  in  the  steel 
to  the  amount  of  .07  per  cent,  and  consisted  of  iron 
and  vanadium  with  indications  of  the  presence  of  an- 
other not  yet  identified  element.  Thus  it  appears  that 
certain  compounds  of  iron  may  be  formed  in  the  pig- 
iron  which  resist  all  subsequent  oxidizing  influences, 
and  are  found  in  the  refined  products ;  i.  e.,  wrought 
iron  and  steel.  Such  compounds  are  apt  to  be  dis- 
covered in  the  ordinary  silicon  determinations  and  need 
not  be  suspected  in  the  ferric  chloride  residue,  in  the 
case  of  wrought  iron  and  steel,  unless  thus  detected 
beforehand.  The  compound  in  question  may  also  have 
been  introduced  into  the  steel  with  the  final  additions 
of  spiegel,  etc. 


44  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

To  separate  the  slag  and  oxides  of  iron  from  the 
ferric  chloride  residue  it  is  necessary  to  treat  the  same 
with  a  hot  alkali ;  by  this  means  the  silica  is  removed, 
any  free  silicon  being  oxidized  to  silica  with  the  evo- 
lution of  hydrogen  gas.  The  residue  must  then  be 
ignited  in  a  current  of  dry  chlorine  to  remove  iron 
phosphides,  arsenides  etc. 

In  the  case  of  wrought  irons,  which  usually  contain 
considerable  slag  and  oxides  of  iron,  a  sufficient  idea  of 
the  amount  of  these  impurities  can  be  gained  by  simply 
igniting  and  weighing  the  ferric  chloride  residue  after 
washing  thoroughly  with  hot  alkali  and  cold  water  free 
from  air. 

For  steels  this  treatment  will  give  an  approximate 
idea  of  the  amount  of  slag  and  oxide  of  iron  present ; 
but  it  must  be  borne  in  mind  that  the  residue  also  con- 
tains the  phosphides,  sulphides,  etc.  of  iron  and  pos- 
sibly other  iron  compounds.  The  method  is,  therefore, 
in  this  case,  only  suitable  as  a  comparative  test  at  the 
same  steel-works  where  the  chemical  composition  is 
kept  tolerably  uniform. 

k.  Determination  of  Arsenic.  Ten  grams  of  drill- 
ings are  dissolved  in  dilute  nitric  acid  in  a  beaker 
and  evaporated  with  sulphuric  acid  to  complete  expul- 
sion of  the  nitric  acid.  To  facilitate  the  removal  of 
the  nitric  acid  the  mass  should  be  stirred  with  a  glass 
rod.  The  heating  is  continued  until  the  mass  has  be- 
come so  dry  that  it  can  be  shaken  down  into  a  half- 
liter  flask.  The  mass  is  mixed  in  the  half-liter  flask 


ANALYSIS    OF   WROUGHT    IRON    AND    STEELS.  45 

with  about  15  grams  of  powdered  ferrous  sulphate.  Into 
the  neck  of  the  flask  is  inserted  a  rubber-stopper  con- 
taining a  funnel-tube  and  a  bent  glass  tube  from  which 
a  50  cubic  centimetre  pipette  is  suspended  by  means 
of  a  rubber-tube.  The  lower  end  of  the  pipette  dips 
down  into  a  beaker  filled  with  water.  Through  the 
funnel-tube  about  100  cubic  centimetres  of  strong  hydro- 
chloric acid  are  run  in,  and  the  flask  gently  heated. 
The  ferrous  sulphate  reduces  the  arsenic  acid  to 
arsenious  acid  and  the  arsenic  distils  over  into  the 
beaker  as  arsenic  chloride  (As  C18).  After  about  half 
an  hour,  when  the  pipette  has  become  warm,  all  the 
arsenic  present  has  been  separated.  By  saturating  the 
solution  in  the  beaker  with  sulphuretted  hydrogen  at  a 
temperature  of  about  70°  C.  and  driving  off  the  excess 
of  H2  S  with  a  current  of  carbonic  acid  gas  passed 
through  the  solution,  we  obtain  a  yellow  precipitate  of 
As2  S3.  This  is  filtered  off  rapidly  and  dissolved  in 
aqua  regia.  After  boiling  off  excess  of  acid  the  arsenic 
is  precipitated  in  a  100  cubic  centimetre  beaker  as 

\NH  r As  O*  +  6  H2  O \  by  magnesia   mixture,  in  exactly 

the  same  manner  as  is  phosphorus.  This  precipitate, 
when  gently  ignited  in  a  slow  current  of  oxygen,  yields 
Mg2  As2  Oy,  containing  48.42  per  cent  of  arsenic. 

/.  Determination  of  Titanium.  The  solution  of 
ten  grams  in  H  Cl  from  the  bromine  method  for 
sulphur  may  be  used.  Add  to  this  solution  a  small 
quantity  of  bromine,  so  as  to  oxidize  only  a  small  part 


46  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  the  iron.  By  now  making  a  basic  acetate  separation 
of  that  portion  of  the  iron  thus  oxidized  we  obtain 
all  the  titanium  with  the  iron  precipitate.  Redissolve 
the  basic  acetate  in  H  Cl  and  precipitate  with  am- 
monia. Ignite  the  precipitate  in  a  platinum  crucible, 
evaporate  with  hydrofluoric  acid  and  ignite  again,  after 
adding  a  little  sulphuric  acid.  Treat  the  residue  with 
strong  hydrochloric  acid.  This  leaves  any  titanic  acid 
(Ti  O2)  undissolved.  The  latter  may  then  be  ignited 
and  weighed  as  Ti  O2,  containing  60  per  cent  of 
titanium. 

m.  Tracing  of  Vanadium.  Vanadium,  when  pres- 
ent, usually  accompanies  the  silica.  By  removing  the 
latter  with  hydrofluoric  acid  and  igniting  the  residue 
the  vanadic  acid  fuses  and,  on  cooling,  forms  a  beauti- 
ful crimson  crystalline  mass.  By  fusing  silica  con- 
taining vanadium  with  sodium  carbonate  a  greenish 
yellowish  mass  is  obtained  which  dissolves  in  water, 
leaving  some  oxide  of  iron.  In  the  solution  the  re- 
actions for  vanadium  may  be  obtained. 

n.  Determination  of  Chromium.  The  following 
method  is  the  one  most  commonly  used.  It  should  here 
be  pointed  out,  however,  that  the  filtrate  from  the  Mn 
O2  precipitate  in  the  nitric  acid  and  chlorate  of  potash 
method  for  determining  manganese  (see  p.  29)  con- 
tains as  chromic  acid  most  and  possibly  all  the  chro- 
mium present  in  the  metal.  This  could  probably  be 
made  the  basis  for  a  rapid  method  of  determining 
chromium  in  irons  and  steels. 

* 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  47 

One  to  five  grams  of  sample  are  dissolved  by  boiling 
with  hydrochloric  acid,  1.12  specific  gravity,  in  a  flask 
of  half  a  liter  capacity.  The  neck  of  the  flask  should 
be  closed  with  a  rubber-stopper.  Through  a  hole  in 
this  rubber-stopper  is  inserted  a  glass  tube,  attached  to 
which  is  a  piece  of  rubber-tubing.  This  rubber-tubing 
is  closed  at  the  other  end  by  means  of  a  piece  of  glass- 
rod  and  provided  with  a  longitudinal  slit  through  which 
the  steam  can  escape  during  boiling,  whilst  no  air  can 
enter.  Oxidation  is,  by  this  arrangement,  almost  com- 
pletely prevented. 

When  all  is  dissolved,  the  flask  is  nearly  filled  with 
cold  water  and  the  solution  neutralized  with  powdered 
carbonate  of  baryta  in  excess.  If  much  free  acid  be 
present,  some  carbonate  of  soda  should  be  added  before 
the  carbonate  of  baryta.  Cork  the  flask  tightly  and 
allow  to  stand  for  twenty-four  hours  at  ordinary  tem- 
perature with  occasional  shaking.  Cr2  O3  and  a  little 
Fe2  O3  are  hereby  precipitated,  whilst  all  Fe  C12,  Mn 
C12  etc.  remain  in  the  solution.  Filter  off  the  pre- 
cipitate, together  with  the  excess  of  carbonate  of  baryta, 
wash  with  hot  water  and  redissolve  in  H  Cl  by  boiling. 
To  the  boiling  solution  thus  obtained  add  ammonia, 
and  boil  off  the  excess  of  the  latter.  The  Cr2  O3  and 
Fe2  O3  are  hereby  precipitated,  whilst  all  the  barium  re- 
mains in  solution.  Filter  off  the  precipitate,  wash  well 
with  hot  water,  dry,  ignite  and  fuse  in  a  platinum  cru- 
cible with  carbonate  of  soda  and  a  little  nitrate  of  soda. 
Extract  the  fused  mass  with  hot  water  and  filter  off 


48  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

the  residual  iron  oxide.  The  filtrate  contains  all  the 
chromium  as  the  yellow  sodium  chromate.  Acidify  the 
filtrate  with  H  Cl,  add  a  little  sodium  sulphite  and  heat 
to  boiling.  The  Cr  O3  is  hereby  instantly  reduced  to 
Cr2  O3.  To  the  boiling  green  solution  thus  obtained 
add  ammonia  in  slight  excess.  The  color  of  the  solu- 
tion changes  to  violet  at  first;  but,  on  continued  boil- 
ing, the  green  chromic  oxide  is  precipitated.  When 
the  smell  of  ammonia  has  almost  completely  disap- 
peared the  chromic  oxide  is  filtered  off,  ignited  in  a 
platinum  crucible  and  weighed  as  Cr2  O3,  containing 
68.62  per  cent  of  chromium. 

If  the  chromium  steel  contains  silicon,  it  will  be  found 
as  sodium  silicate  together  with  the  sodium  chromate 
and  should  be  separated  by  evaporation  in  the  usual  way 
before  precipitating  the  chromic  oxide  with  ammonia. 

o.  Determination  of  Tungsten.  Three  to  five 
grams  of  sample  are  treated  in  exactly  the  same  way 
as  in  a  phosphorus  determination  with  the  exception 
that  the  heating  need  not  be  so  strong  and  protracted. 
Presence  of  tungsten  is  at  once  indicated  by  the  yellow 
color  of  the  tungstic  acid  (W  O3)  which  all  separates 
with  the  silica. 

The  silica  and  tungstic  acid  are  filtered  off  and 
washed  with  water,  to  which  a  little  H  Cl  has  been 
added  to  prevent  the  W  O3  from  passing  through  the 
filter.  The  tungstic  acid  is  then  dissolved  on  the  filter 
in  hot  ammonia,  and  is  thus  separated  from  the  silica. 
The  filtrate  is  concentrated  so  as  to  allow  of  its  being 


ANALYSIS    OF    WROUGHT    IRON    AND    STEELS.  49 

poured  into  a  weighed  platinum  crucible,  in  which  it  is 
evaporated  to  dryness,  ignited,  and  weighed  as  W  O3, 
containing  79.3  per  cent  of  tungsten. 

JB. —  Analysis  of  fig-iron. 

The  analysis  of  pig-iron  is,  with  a  few  modifications, 
similar  to  that  of  wrought  irons  and  steels. 

a.  Determination  of  Graphite.     To  determine  sep- 
arately the  graphite  and  the  combined  carbon,  we  first 
determine    the    total    carbon    by    the    double    chloride 
method  (p.  7).     The  graphite  is  determined  by  dissolv- 
ing five  grams  of  drillings  in  dilute  hydrochloric  acid 
and  filtering  off   the  residue   in    the   platinum   funnel. 
This  residue  must  now  be  freed  from  all  nongraphitic 
carbon.     This  is  done  by  washing  first  with  hot  water 
and   hot   ammonia  and    then  with  alcohol,  ether,  and, 
finally,  again  with  water.     A  brisk  evolution  of  hydrogen 
gas  takes  place  when  washing  with  hot  ammonia,  owing 
to  the  oxidation  of  silicon.     The  graphite  is  then  burnt 
out  in  the  platinum  tube  as  usual  and  deducted  from 
the  total  carbon.     This  gives  us  both  the  graphite  and 
the  combined  carbon. 

b.  Determination  of  Silicon.     For  the   determina- 
tion of  silicon  the  sulphuric  acid  method  must  be  used 
exclusively.     The  silica  cannot  be  obtained  pure  in  the 
determination  of  phosphorus,  as  in  the  case  of  wrought 
iron  and  steel,  whilst  the  sulphuric  acid  method  yields  a 
perfectly  white  silica  with  possibly  some  vanadic  acid 
adhering  to  it.     The  vanadic  acid  imparts  a  yellowish 


50  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

brown  color  to  the  silica.  It  may,  to  some  extent,  be 
removed  by  washing  with  ammonia  or  with  hot  hydro- 
chloric acid. 

In  the  case  of  very  silicious  pig-irons  one  gram  is 
sufficient  for  a  determination  of  silicon. 

c.  Determination  of  Sulphur.    The  bromine  method 
is  in  most  cases  applicable,  but  it  is  advisable  always  to 
use  the  aqua  regia  method  as  well,  pig-irons  being  apt 
to  'contain  more  metals  that  are  precipitated  by  H2  S 
than  do  wrought  iron  and  steel.     It  is  to  be  remem- 
bered, however,  that  it  is  extremely  difficult  to  obtain 
the    barium    sulphate    perfectly   pure    when    using   the 
aqua  regia  method  for  pig-iron. 

d.  Slag  generally  occurs  in  pig-iron  and  is  found  in 
the  ferric   chloride   residue  (p.  41).     This   slag   carries 
lime,   magnesia,    alumina,   silica   etc.,   as   do    all    blast- 
furnace slags.     The  ferric  chloride  residue  may  be  ana- 
lyzed completely  according  to  directions  given  below 
for  iron  ores. 

C.  —  Analysis  of  Spiegel  and  Ferromanganese. 

The  alloys  of  iron  and  manganese  that  are  now 
manufactured  may  contain  a  proportion  of  manganese 
varying  from  a  few  per  cent  to  80  or  90  per  cent.  The 
determination  of  the  manganese  in  these  alloys  is  a 
most  important  one.  If,  as  for  most  practical  purposes, 
it  be  sufficient  to  determine  the  manganese  to  within 
one-half  per  cent,  the  simplest  way  is  to  determine  the 
iron  and  to  ascertain  the  manganese  by  difference, 


ANALYSIS    OF    SPIEGEL    AND    FERROMANGANESE.  5! 

allowing  for  carbon,  silicon,  etc.,  according  to  the  follow- 
ing  table :  — 

When  the  iron  contained  is 

Less  than  20  per  cent,  deduct  7.5  per  cent. 
Between  20  and  45  per  cent,  deduct  6.5  per  cent. 
Between  45  and  65  per  cent,  deduct  6.0  per  cent. 
65  per  cent  and  upwards,  deduct  5.5  per  cent. 

This  indirect  method  is  only  applicable  to  manganese 
alloys  manufactured  in  the  blast-furnace  from  manga- 
niferotis  ores.  Many  manganese  alloys  are  manufact- 
ured in  crucibles  and  for  these  the  table  cannot  be 
used.  The  iron  is  determined  by  dissolving  .5  to  2 
grams  of  the  sample  in  dilute  sulphuric  acid  and 
titrating  with  the  bichromate  of  potash  (see  p.  33).  For 
alloys  very  rich  in  manganese,  however,  this  bichromate 
titration  is  not  suitable  on  account  of  the  brown  pre- 
cipitate which  the  ferricyanide  of  potash  gives  with 
the  manganese.  This  brown  precipitate  obscures  the 
final  change  of  color.  As  a  rule,  this  indirect  method 
may  be  well  used  for  alloys  containing  about  50  per 
cent  of  Mn  and  below. 

The  same  methods  as  are  used  in  the  case  of 
wrought  iron  and  steel  may  also  be  here  used  for  the 
determination  of  manganese,  with  the  following  modifi- 
cations :  The  quantity  of  sample  weighed  out  must 
be  proportioned  according  to  the  amount  of  manga- 
nese present,  so  that  a  smaller  quantity  be  used  for 
a  larger  percentage  of  manganese  and  vice  versa.  If 
the  amount  of  manganese  exceeds  the  amount  of  iron 


52  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

present,  about  one  gram  of  pure  iron  wire  must  be 
added.  A  still  larger  amount  of  wire  is  not  objec- 
tionable ;  in  fact,  it  ought  always  to  be  added  when 
using  the  nitric  acid  and  chlorate  of  potash  method 
for  alloys  rich  in  manganese.  If  an  excess  of  iron  be 
not  present,  the  manganese  cannot  be  completely  pre- 
cipitated as  Mn  O2.  This  is  a  most  important  fact, 
although  we  have  no  satisfactory  explanation  of  the 
cause  thereof.  A  safe  rule  to  follow  is  to  combine 
the  manganese  alloy  to  be  operated  upon  with  such  a 
proportion  of  iron  wire  that  a  total  sample  of  five 
grams  will  not  contain  more  than  two  per  cent  of 
manganese. 

In  the  case  of  alloys  very  rich  in  manganese,  say  75 
to  90  per  cent,  it  is  necessary  to  use  such  a  small  quan- 
tity of  the  material  to  be  analyzed  that  the  nitric  acid 
and  chlorate  of  potash  method  with  subsequent  titration 
is  not  to  be  recommended  and  the  following  simple 
method  is  preferred :  Weigh  out  one-tenth  gram,  and 
treat  as  for  a  phosphorus  determination.  Make  two 
successive  basic  acetate  precipitations  (p.  30),  without 
filtering  off  the  silica,  and  determine  the  manganese 
in  the  filtrates  with  bromine  and.  ammonia  as  usual. 
Sometimes  even  three  basic  acetates  are  necessary. 

Carbon  can  be  determined  by  combustion,  as  in 
wrought  iron  and  steel,  except  in  the  case  of  the  higher 
manganese  alloys.  When  these  are  treated  with  the 
double  chloride,  a  portion  of  the  carbon  is  apt  to  escape 
in  the  form  of  gaseous  hydrocarbons.  In  such  cases 


ANALYSIS    OF    SILICON-IRON,    ETC.  53 

five  grams  of  the  finely  pulverized  material  should  be 
mixed  with  pure  cupric  oxide  in  a  platinum-funnel,  and 
burned  in  a  stream  of  oxygen  for  one  hour  or  longer. 
The  burning  and  the  weighing  of  the  bulbs  should  be 
repeated  once  or  twice,  to  make  sure  that  all  the  carbon 
is  burnt  out.  Some  chromium  steels  must  be  treated 
in  the  same  way,  as  they  are  not  completely  decomposed 
by  the  double  chloride. 

Otherwise  the  analysis  of  the  manganese  alloys  is 
similar  to  the  analysis  of  wrought  iron  and  steel.  Sul- 
phur, however,  rarely  occurs  except  in  the  smallest 
traces ;  in  fact,  it  is  greatly  to  be  suspected  that,  when- 
ever sulphur  is  found,  it  is  due  to  impure  reagents  or 
incorrect  manipulations. 

When  applying  the  method  for  copper  determination, 
it  must  be  borne  in  mind  that  we  have  to  purify  the 
first  precipitate  of  copper  subsulphide  not  only  from 
iron,  but  also  from  manganese,  and  that,  therefore,  some 
bromine  must  be  used  along  with  the  ammonia. 

D.  —  Analysis  of  Silicon-iron,  and    Silicon-man- 

ganese-iron. 

There  is  nothing  specially  to  be  remarked  concerning 
the  analysis  of  these  alloys,  except  that  the  silica,  even 
when  obtained  by  the  sulphuric  acid  method,  is  apt  to 
contain  many  impurities,  particularly  vanadic  acid.  The 
silica  should,  therefore,  after  weighing  it  in  the  impure 
state,  be  volatilized  with  hydrofluoric  acid,  and  the  resi- 
due ignited,  weighed,  and  the  weight  deducted  from  the 


54  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

total  weight.  A  little  sulphuric  acid  must  be  used, 
together  with  the  hydrofluoric  acid,  to  prevent  any 
partial  volatilization  of  the  residue. 

It  is  natural  that  alloys  like  the  ones  in  question 
should  contain  more  rare  impurities  even  than  pig-iron, 
the  reducing  action  of  the  blast-furnace  required  in 
their  manufacture  being  much  greater  than  is  the  case 
with  the  latter. 


CHAPTER   III. 

DETERMINATION     OF     THE     MOST    IMPORTANT    INGREDIENTS 
IN    IRON    ORES,    SLAGS,    LIMESTONES,    FUEL,    ETC. 

A. — Analysis  of  Iron  Ores. 

BY  iron  ores  we  mean  such  minerals  as  are  used 
for  the  manufacture  of  iron.  Iron  ores  consist  of  the 
oxides,  the  hydrated  oxides,  and  the  carbonates  of  iron, 
contaminated  with  varying  amounts  of  rocky  or  earthy 
matter.  The  residues  after  burning  iron  pyrites,  pud- 
del-slags,  etc.,  are  occasionally  used  as  iron  ores. 

Manganese  ores  and  manganiferous  iron  ores  (car- 
bonates of  iron  and  manganese)  also  play  an  important 
part  in  modern  iron  and  steel  manufacture. 

In  practical  work  it  is  often  only  necessary  to  deter- 
mine the  most  important  elements  entering  into  the 
composition  of  iron  ores,  such  as  iron,  phosphorus, 
manganese,  silica,  insoluble  residue,  etc.  As  the  direct 
methods  for  determining  these  substances  are  very  simi- 
lar to  the  corresponding  methods  employed  in  the  case 
of  wrought  iron  and  steel,  they  are  here  first  given; 
and  the  directions  for  making  a  complete  analysis  of 
iron  ores,  considered  as  minerals,  will  follow  (see  p.  61). 

a.  Determination  of  the  Total  Iron.  Dissolve 
about  one  gram  of  finely-ground  ore  in  dilute  sulphuric* 

*  Or  in  hydrochloric  acid,  with  subsequent  addition  of  sulphuric  acid  and  ex- 
pulsion of  the  hydrochloric  acid. 


56  NOTES    ON    THE    CHEMISTRY    OF   IRON. 

I 

acid  by  boiling.  When  dissolved  as  far  as  possible, 
add  some  water  and  sulphite  of  soda,  powdered,  in  such 
excess,  that  the  solution  assumes  a  dark-red  color. 
After  some  heating,  add  more  sulphuric  acid,  and  boil 
until  all  smell  of  sulphurous  acid  has  disappeared. 
The  solution  is  now  colorless,  or  perhaps  slightly 
brownish,  owing  to  organic  matter,  and  all  the  iron  is 
in  the  state  of  Fe  O.  We  may  thus  determine  the 
total  iron  by  titrating  with  the  standard  bichromate  of 
potash,  as  described  above.  This  method  will  give  the 
iron  within  about  .5  per  cent.  This  is  for  most  prac- 
tical purposes  sufficiently  accurate.  A  little  iron  nearly 
always  remains  in  the  residue,  a  little  sulphurous  acid 
remains  in  the  solution,  and  a  little  Fe2  O3  remains 
unreduced ;  all  these  circumstances  interfere  with  ob- 
taining a  closer  result. 

Thiosulphate  of  soda  cannot  be  used  instead  of  the 
sulphite,  owing  to  the  formation  of  tetrathionic  acid, 
which  has  a  reducing  action  upon  the  bichromate. 

Zinc  also  cannot  conveniently  be  used  as  a  reducing 
agent,  owing  to  the  brown  precipitate  which  it  forms 
with  ferricyanide  of  potash.  Zinc  can  be  used  with  a 
standard  oxidizing  solution  of  permanganate  of  potash ; 
but  the  disadvantages  of  the  permanganate  solution 
are  so  great,  that  it  has  almost  everywhere  been  aban- 
doned in  favor  of  the  bichromate. 

It  is  better  to  use  sulphuric  acid  than  hydrochloric 
acid,  for  the  reason  that  the  final  reaction  with  the  ferri- 
cyanide is  sharper. 

*  This  can  be  obviated  by  using  some  H  Cl  with  the  solution  of  ferricyanide. 


ANALYSIS    OF    IRON    ORES.  57 

b.  Determination  of  the  Iron  present  as  Ferric 
Oxide  (Fe2  O3).  This  method  is  carried  out  by  dis- 
solving 1.5  grams  of  ore  in  hydrochloric  acid,  and 
titrating  with  a  standard  solution  of  protochloride  of 
tin.  Use  is  made  of  a  burette  and  a  porcelain  dish 
exactly  similar  to  those  used  in  the  bichromate  method. 
The  standard  protochloride  of  tin  solution  is  also  kept 
in  a  jar  similar  to  that  used  for  the  bichromate ;  but, 
owing  to  the  rapid  absorption  of  oxygen  from  the  air 
by  the  protochloride  of  tin,  it  should  be  covered  with  a 
layer  of  petroleum.  When  thus  protected,  it  keeps  for 
a  very  long  time  at  its  original  strength.  From  the 
burette  the  standard  solution  is  run  into  the  ore  solu- 
tion, which  should  be  boiling  hot,  and  have  a  large 
excess  of  hydrochloric  acid  present,  say  about  25  cubic 
centimetres  of  H  Cl,  1.12  specific  gravity,  for  every 
one-tenth  of  a  gram  of  iron.  It  is  easy  to  observe  the 
final  reaction  when  the  solution  turns  colorless.  The 
reaction  is  — 

Fe2  C16  +  Sn  C12   =   2  Fe  C12  +  Sn  C14. 

The  protochloride  of  tin  solution  is  prepared  by  dis- 
solving metallic  tin  in  hydrochloric  acid,  1.19  specific 
gravity,  until  evolution  of  gas  has  ceased,  pouring  off 
from  excess  of  tin  and  diluting  with  H  Cl,  1.12  spe- 
cific gravity,  to  ten  times  the  volume  of  the  concen- 
trated solution.  The  salt  Sn  C12  can  be  used  instead 
of  metallic  tin.  The  Sn  C12  solution  is  standardized  by 
means  of  a  ferric-chloride  solution  of  known  strength. 


58  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

The  Fe2  C16  solution  should  have  10  grams  of  iron  in 
one  liter,  and  may  be  prepared  either  from  iron  wire  or 
from  ferric  oxide.  10.04  grams  of  iron  wire,  or  14.2857 
grams  of  Fe2  O3,  give  10  grams  of  iron.  The  iron 
wire  is  dissolved  in  H  Cl  and  boiled  with  a  little 
K  Cl  O3  until  all  Cl  is  driven  off.  The  ferric  oxide  is 
simply  dissolved  in  strong  H  Cl.  Fifty  cubic  centime- 
tres of  this  iron  solution  contain  .5  gram  of  iron,  and 
about  25  cubic  centimetres  of  the  above  tin  solution 
will  be  required  for  this  quantity.  Three  or  four  check 
titrations  should  be  made,  and  the  tin  solution  re-stand- 
ardized frequently.  By  observing  the  directions  given, 
viz.,  to  have  the  solution  boiling  hot,  and  to  use.  a  large 
excess  of  H  Cl,  there  is  no  need  of  adopting  the  more 
troublesome  method  given  in  most  handbooks,  viz.,  to 
run  in  excess  of  Sn  C12,  and  then  titrate  back  with 
iodine  solution  and  starch-paste  (2  Sn  C12  -)-  2  I  = 
Sn  C14  -)-  Sn  I2).  By  the  protochloride  of  tin  method 
we  obtain  accurately  the  amount  of  Fe2  O3  present  in 
the  ore.  Having  thus  previously  determined  the  total 
iron,  we  can  obtain,  by  difference,  the  amount  of  iron 
present  as  Fe  O.  In  magnetic  iron  ores  the  propor- 
tion between  iron  as  Fe2  O3  and  iron  as  Fe  O  is  about 
2:1.  When  dissolving  ores  for  iron  determinations 
it  is  suitable  to  use  an  assay-flask  with  a  narrow  mouth, 
into  which  a  rubber-stopper  is  inserted  (p.  47).  No  oxi- 
dation of  the  Fe  O  present  need  then  be  feared. 

c.  Determination  of  Phosphorus.     Five  grams  of 
the  finely  ground  ore  are  dissolved  on  the  hot  iron  plate 


ANALYSIS    OF    IRON    ORES.  59 

in  a  beaker  in  strong  H  Cl,  with  the  addition  of  a  little 
H  NO3.  After  a  short  heating  at  a  moderate  heat 
redissolve  the  dry  mass  in  strong  H  Cl,  concentrate 
by  evaporation,  add  water  and  filter  off  the  insoluble 
residue.  Then  proceed  exactly  as  for  a  phosphorus 
determination  in  steel.  If  the  residue  should  happen 
to  be  very  large  or  look  very  dark,  it  may  still  be  sus- 
pected to  contain  some  phosphorus.  In  this  case  fuse 
the  residue  in  a  platinum  crucible  with  sodium-carbo- 
nate, dissolve  the  mass  in  H  Cl  and  water,  separate  the 
silica  by  evaporation  as  usual,  test  the  filtrate  for  phos- 
phorus with  molybdic  acid  solution,  and,  if  phosphorus 
be  found,  add  the  filtrate  to  the  one  first  obtained. 

d.  Determination  of  Sulphur.  Five  grams  of  ore 
are  boiled  with  aqua  regia  and  evaporated  to  gentle 
dryness  on  the  iron  plate.  The  residue  may  contain, 
besides  earthy  matter  and  silica,  insoluble  sulphates, 
such  as  sulphates  of  lime,  lead  and  baryta.  The  sul- 
phate of  lime  passes  into  solution  on  continued  boiling 
with  plenty  of  water,  whilst  the  other  sulphates  remain 
with  the  residue,  which  should  be  tested  qualitatively 
afterwards.  After  filtering  off  the  residue  the  sulphur 
is  precipitated  and  determined  exactly  as  in  iron  and 
steel.  The  residue,  if  lead  and  barium  be  present, 
should  be  fused  with  carbonate  of  soda.  Sodium  sul- 
phate, sodium  silicate,  etc.,  are  thus  formed  ;  they  can 
be  dissolved  with  water  and  the  filtrate  examined 
for  H2  SO4  after  separating  the  Si  O2  in  the  usual 
way. 


6O  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

e.  Determination  of  Manganese.  Sometimes,  in 
the  case  of  so-called  manganiferous  iron  ores,  a  special 
and  quick  method  for  manganese  is  required.  We  can 
here  apply  the  same  methods  as  for  steel,  using  nitric 
acid  and  chlorate  of  potash,  or  we  may  proceed  accord- 
ing to  the  directions  on  p.  5 1  for  high  manganese  alloys, 
separating  the  iron  by  basic  acetates.  The  only  im- 
purities which  may  interfere  seriously  with  the  accuracy 
of  such  manganese  determinations  in  ores  are  baryta 
and  lime.  In  the  nitric  acid  and  chlorate  of  potash 
method,  with  titration,  the  danger  from  these  causes  is 
comparatively  small.  In  the  basic  acetate  and  bromine 
and  ammonia  method,  however,  baryta,  if  present,  must 
be  removed  before  precipitating  the  manganese.  The 
baryta  is  removed  by  evaporating  the  H  Cl  solution  of 
the  ore  with  H2  SO4,  diluting  with  water  and  filtering 
off  the  sulphate  of  baryta.  The  manganese  precipitate 
from  the  bromine  and  ammonia  process  may  be  freed 
from  contaminating  lime  by  simply  redissolving  and 
reprecipitating  with  bromine  and  ammonia. 

Manganese  ores,  consisting  of  the  higher  oxides  of 
manganese,  are  much  used  in  the  manufacture  of  the 
higher  alloys  of  iron  and  manganese.  Such  ores  may 
be  analyzed  according  to  the  methods  already  given. 

/.  Determination  of  Moisture  and  Loss  on  Igni- 
tion. The  moisture  is  determined  by  drying  a  large 
quantity,  say  100  grams,  of  ore  at  120°  C.  and  weighing. 

The  loss  on  ignition  is  determined  by  igniting  about 
one  gram  of  ore  in  a  platinum  crucible.  The  loss 


ANALYSIS    OF      IRON    ORES.  6 1 

represents  chiefly  water,  carbonic  acid,  organic  matter, 
and  possibly  some  sulphur. 

g.  Complete  Analysis  of  Iron  Ores.  Half  a  gram 
of  finely  ground  ore  is  fused  in  a  platinum  crucible 
with  about  3  grams  of  carbonate  of  soda.  If  the  ore 
be  very  rich  in  iron,  it  is  better  to  fuse  the  insoluble 
residue,  obtained  by  treating  5  grams  of  ore  with  H  Cl, 
so  as  to  obtain  a  larger  quantity  of  material  in  which 
to  determine  the  small  amounts  of  other  elements  than 
iron  present.  After  fusion  the  mass  is  dissolved  in  H 
Cl  and  water,  putting  the  crucible  into  the  beaker,  to 
remove  all  traces  of  the  fusion.  When  much  manga- 
nese is  present,  which  is  indicated  by  a  deep  blue-green 
color  of  the  mass,  it  is  best  to  remove  the  mass  and 
dissolve  it  in  a  separate  beaker,  treating  the  crucible 
with  acid  in  another  beaker.  Hydrochloric  acid  evolves 
chlorine  with  the  higher  oxides  of  manganese,  whereby 
the  platinum  would  be  seriously  attacked. 

In  the  fusion  with  carbonate  of  soda,  sodium  silicate, 
sodium  phosphate,  sodium  sulphate,  sodium  aluminate, 
sodium  manganate,  etc.,  are  formed  ;  whilst  the  bases, 
viz.,  the  iron,  magnesium,  calcium,  some  manganese 
and  some  aluminium,  are  separated  in  the  fusing,  fluid 
mass  as  oxides.  By  extracting  with  water  only  it  would 
therefore  be  impossible  to  effect  a  complete  separation 
of  the  silica  from  the  bases.  The  alumina  and  the 
manganese  will  in  part  go  into  solution,  and  in  part 
remain  with  the  residue.  We  therefore  proceed  as 
usual,  using  H  Cl  with  the  water,  and  separating  the 


62  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

silica  by  evaporating  to  gentle  dryness.  The  dry  mass 
is  then  moistened  with  a  little  strong  H  Cl  and  dis- 
solved in  water ;  the  silica  is  then  filtered  off  and  washed 
with  H  Cl  and  water,  ignited  and  weighed. 

If  the  fusion  was  made  on  an  insoluble  residue,  as 
mentioned  above,  the  filtrate  from  the  silica  is  joined 
with  the  H  Cl  solution  previously  obtained.  In  either 
case  the  operations  are  essentially  the  same. 

In  the  filtrate  from  the  silica  make  a  basic  acetate 
precipitation  (p.  31).  The  filtrate  from  this  contains 
the  manganese,  the  lime,  and  the  magnesia,  whilst  the 
basic  acetate  precipitate  contains  the  iron,  the  alumina, 
the  phosphoric  acid,  the  titanic  acid,  and  possibly  traces 
of  silica.  Copper  and  lead  are  only  in  part  carried 
down  with  the  basic  acetate  precipitate,  whilst  antimony 
and  arsenic,  if  present,  accompany  the  same  completely. 
The  basic  precipitate  is  redissolved  in  H  Cl,  and  again 
precipitated  with  ammonia  in  small  excess  at  a  boiling 
heat.  This  precipitate  is  ignited  and  weighed,  then 
redissolved  in  H  Cl,  whereby  any  titanic  acid  and  silica 
are  left  behind.  If  the  iron  and  phosphorus  have  been 
previously  determined,  we  can  now  obtain  the  alumina 
from  the  difference  between  the  total  weight  of  the  pre- 
cipitate and  the  Fe2  O3,  the  -  P2  O5,  and  the  Ti  O2  + 
Si  O2  in  the  insoluble  residue.  It  is,  however,  more 
accurate  to  make  a  special  determination  of  the  iron 
in  the  solution  obtained  after  the  separation  of  the  Ti 
and  Si,  and  for  this  purpose  we  make  use  of  a  very 
sharp  method,  as  follows :  Nearly  neutralize  the  iron 


ANALYSIS    OF    IRON    ORES.  63 

solution  last  referred  to  with  carbonate  of  soda,  only 
using  such  a  proportion  of  same  as  will  contain  not 
more  than  .25  gram  of  iron.  Add  about  4  grams  of 
iodide  of  potassium,  using  a  small  flask  with  tightly 
fitting  ground-stopper,  so  that  the  air  can  be  well  ex- 
cluded. The  following  reaction  takes  place :  — 

Fe2  C16  +  2  KI  =  2  Fe  C12  +  2  K  Cl  -f  2  I. 

The  liberated  iodine  dissolves  in  the  excess  of  potassium 
iodide.  The  reaction  is  promoted  by  slight  warming. 
We  then  introduce  into  the  dark-red  solution  from  a 
porcelain  crucible  a  weighed  quantity  of  pure  mercury, 
say  about  6  grams,  and  shake  until  the  solution  has 
become  colorless.  The  following  reaction  has  then 
taken  place :  Hg  -f-  2  I  =  Hg  I2.  During  the  shak- 
ing a  current  of  C  O2  should  be  passed  through  the 
solution,  to  exclude  the  air ;  if,  however,  the  stopper  fits 
well,  and  the  solution  reaches  nearly  to  the  top,  the 
above  precaution  becomes  less  necessary.  When  the 
brownish  color,  due  to  the  free  iodine,  has  turned  light 
yellow,  a  little  starch-paste  is  added,  which  gives  the 
solution  a  blue  color ;  and  when  this  finally  disappears 
it  is  a  sharp  indication  that  all  the  free  iodine  has  com- 
bined with  mercury.  From  the  above  formulas  we  find 
that  one  part  of  mercury,  dissolved  as  iodide,  corre- 
sponds to  .56  part  of  iron.  The  remaining  mercury 
is  therefore  poured  back  into  its  porcelain  crucible, 
dried  by  contact  with  filter  paper  and  weighed,  and 
the  iron  calculated  from  the  loss  which  the  mercury  has 


64  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

sustained.  Another  very  good  method  of  determining 
the  liberated  iodine  is  to  use  a  standard  solution  of 
thiosulphate  of  soda,  when  the  following  reaction  takes 

place :  — 

2  Na2  S2  O3  +  2  I   =    2  Na  I  +  Na2  S4  O6. 

The  thiosulphate  must  be  restandardized  so  often, 
however,  that  its  use  becomes  inconvenient  in  practice. 
The  filtrate  from  the  basic  acetate  precipitate  is  ren- 
dered ammoniacal,  the  manganese  precipitated  with 
bromine  and  determined  as  usual.  The  filtrate  from 
the  manganese  contains  more  ammoniacal  salts  than 
can  be  conveniently  handled.  The  best  manner  of 
removing  them  is  to  evaporate  in  a  tall  beaker  as  far 
as  possible  without  spitting,  and  then  to  cautiously  add 
strong  nitric  acid.  Red  nitric  oxide  fumes  are  given  off, 
and  on  continued  addition  of  acid  and  evaporation  the 
ammoniacal  salts  are  rapidly  and  completely  removed. 
The  residue  in  the  beaker -is  dissolved  in  a  little  H  Cl 
and  some  cold  water  and  rendered  slightly  ammoniacal. 
A  solution  of  ammonium  oxalate  —  about  20  cubic  centi- 
metres of  the  concentrated  solution  —  is  then  added, 
together  with  a  little  more  ammonia.  Calcium  oxalate 
is  precipitated,  and  magnesium  oxalate  remains  in  solu- 
tion. After  settling,  which,  if  the  amount  of  precipi- 
tate be  very  small,  requires  twelve  hours,  the  calcium 
oxalate  is  filtered  off  and  washed,  first  with  cold,  then 
with  hot  water.  The  latter  should  be  taken  up  in  a 
separate  beaker,  to  prevent  the  precipitation  of  diffi- 
cultly soluble  magnesium  oxalate.  A  double  filter 


ANALYSIS    OF    IRON    ORES.  65 

should  be  used  for  filtering  the  calcium  oxalate.  The 
calcium  oxalate  is  converted  into  Ca  O  by  ignition 
in  a  platinum  crucible  and  weighed  as  such.  To  the 
filtrate  from  the  calcium  oxalate,  which  must  be  cold, 

add   some  microcosmic   salt  solution,    Na    >-PO4    ,  with 

.    H  )        J 

brisk  stirring.  The  microcosmic  salt  precipitates  the 
magnesia  almost  instantly  as  (XT1§  f-PO4  +  6H2O),  which 

\NH4j  /' 

settles  rapidly  to  the  bottom ;  filter,  ignite,  and  weigh 
it  as  in  the  determination  of  phosphorus.  The  Mg2 
P2  O7  contains  36.04  per  cent  of  magnesia  (Mg  O). 

We  have  thus  briefly  described  the  most  important 
points  in  the  analysis  of  iron  ores  in  practice.  As  is 
well  known,  the  absolute  separation  of  the  elements 
in  minerals  is  by  no  means  an  easy  matter,  although  in 
practical  working  the  methods  above  described  will  in 
most  cases  give  fairly  accurate  results. 

Amongst  the  vast  number  of  raw  materials  of  differ- 
ent character  which  are  used  in  the  manufacture  of 
iron,  it  is  only  natural  that  we  should  occasionally  meet 
with  substances  that  are  especially  difficult  to  determine 
in  the  ordinary  course  of  analysis.  Such,  for  instance, 
is  the  combined  occurrence  of  much  titanium  and 
phosphorus  in  some  ores.  No  thoroughly  satisfactory 
method  for  the  separation  of  titanium  and  phosphorus 
is  yet  known.  The  following  method  will  be  found 
useful  in  most  cases.  Fuse  .5  to  i  gram  of  ore  with 
sodium  carbonate  as  usual.  Dissolve  the  mass  in  hydro- 


66  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

chloric  acid  and  water  and,  without  separating  the 
silica,  make  a  basic  acetate  precipitation.  The  filtrate 
from  this  basic  acetate  precipitation  may  be  thrown 
away.  Redissolve  the  basic  acetate  precipitate  in  hydro- 
chloric acid  and  precipitate  with  ammonia.  This  last 
precipitate,  which  contains  the  iron,  silica,  alumina, 
phosphoric  and  titanic  acids,  is  fused  with  sodium  car- 
bonate. By  treating  the  fused  mass  with  water  we 
effect  a  separation  of  the  phosphorus  and  titanium,  the 
latter  remaining  behind  with  the  ferric  oxide  as  acid 
sodium  titanate,  whilst  the  former  passes  into  solution 
as  sodium  phosphate,  together  with  some  sodium  silicate 
and  aluminate.  The  residue  after  treating  with  water 
is  dissolved  in  hydrochloric  acid  and  precipitated  with 
ammonia.  This  precipitate  is  filtered  off,  washed  and 
ignited  in  a  platinum  crucible,  thus  rendering  the  titanic 
acid  insoluble.  The  iron,  alumina,  etc.  are  then  ex- 
tracted with  strong  hydrochloric  acid,  leaving  the  titanic 
acid,  which  is  again  ignited  and  weighed.  The  titanic 
acid  should  be  tested  for  Si  O2  with  hydrofluoric  acid. 

Some  iron  ores  contain  potassium  and  sodium.  A 
special  method  must  be  followed  for  their  determina- 
tion. If  thoroughly  pure  reagents  are  used  the  follow- 
ing method  is  very  suitable.  Volatilize  the  silica  in  a 
few  grams  of  ore  with  H  Fl  and  H  Cl.  Make  a  basic 
acetate  precipitation  in  the  solution  of  the  residue, 
thereby  separating  iron,  alumina,  titanium,  phosphorus, 
arsenic,  etc.  To  the  filtrate  from  the  basic  acetate  pre- 
cipitation add  ammonium  sulphide,  thereby  separating 


ANALYSIS    OF    IRON    ORES.  67 

manganese,  as  well  as  any  zinc,  cobalt,  nickel  and  cop- 
per, etc.,  present  in  the  solution.  The  filtrate  from 
these  sulphides  is  acidified  with  H  Cl,  boiled  to  expel 
H2  S,  and  the  separated  sulphur  filtered  off.  The  fil- 
trate from  the  sulphur  is  concentrated  by  boiling,  and 
the  ammonia  destroyed  by  evaporating  to  dryness  with 
nitric  acid  as  described  heretofore.  In  the  solution  of 
the  residue  the  lime  and  magnesia  are  separated  as 
already  shown,  taking  care  to  use  ammonium  phos- 
phate instead  of  microcosmic  salt  for  the  precipitation 
of  the  magnesia.  The  final  filtrate  from  the  magnesium 
phosphate  contains  the  sodium  and  potassium,  as  well 
as  phosphoric  acid  from  the  ammonium  phosphate  used. 
This  phosphoric  acid  is1  removed  by  adding  a  little 
ferric  chloride  solution  and  making  a  basic  acetate  pre- 
cipitation. The  filtrate  from  this  contains  the  sodium 
and  potassium  free  from  fixed  impurities.  On  ignition 
of  the  evaporated  solution  we  thus  obtain  the  sum  of 
their  chlorides,  and  on  evaporating  and  igniting  the 
latter  with  H2  SO4  we  obtain  the  sum  of  their  sul- 
phates. From  these  data  the  amounts  of  sodium  and 
potassium  are  easily  calculated.  Let  x  be  the  amount 
of  sodium,  y  the  amount  of  potassium  sought. 

Cl  Cl 

Sum  of  chlorides  =  A  =  x  +  ^-  x  +  v  +  TF  v. 

Na         J       K J 

Sum  of  sulphates  =  B  =  x  H ^r-  x  +  v  +  —^  v. 

,    2  Na         J      2  KJ 

By  introducing    the    combining   (atomic)    weights    of 
potassium  and  sodium  respectively  we  obtain,  — 


68  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

A  =  2.54  x  +  1.907. 

B  =  3.08  x  +  2.23  y. 

h.  The  Determination  of  some  Elements  of 
either  rare  occurrence,  or  which  occur  in  very 
small  quantities  in  Iron  Ores,  such  as  Arsenic, 
Antimony,  Lead,  Cobalt,  Nickel,  Zinc,  and  Barium. 

The  ordinary  qualitative  tests  for  these  elements  need 
not  be  described  here  ;  only  a  few  directions  for  their 
determination  will  be  given. 

Arsenic,  Antimony,  and  Lead.  Ten  grams  of  ore  are 
dissolved  in  H  Cl  and  H  NO3,  evaporated  to  dryness 
and  redissolved  with  H  Cl  and  a  large  quantity  of  water. 
The  water  must  be  added  rapidly,  to  prevent  the  sep- 
aration of  basic  salts  of  antimony.  The  iron  is  reduced 
to  the  state  of  Fe  O  by  means  of  ammonium  sulphite, 
and  excess  of  sulphurous  acid  boiled  off.  Sulphuretted 
hydrogen  is  then  passed  through  at  a  temperature  of 
about  70°  C.,  and  the  whole  allowed  to  stand  for  twelve 
hours  in  a  closed  flask.  The  insoluble  substances  are 
then  filtered  off  and  the  sulphides  of  arsenic  and  anti- 
mony extracted  with  ammonium  sulphide.  If  copper 
be  present  it  is  best  to  use  sodium  sulphide,  as  the 
Cu  S  is  not  quite  insoluble  in  the  ammonium  sulphide. 
The  solution  of  arsenic  and  antimony  is  oxidized  with 
K  Cl  O3  and  H  Cl,  then  concentrated  and  mixed  with 
tartaric  acid  and  ammonia,  and  finally  with  magnesia 
mixture.  This  precipitates  arseniate  of  magnesia,  the 
antimony  being  kept  in  solution  by  the  tartaric  acid. 
In  the  filtrate  from  the  arseniate  of  magnesia  the  anti- 


ANALYSIS    OF    IRON    ORES.  69 

mony  is  precipitated  with  H2  S  after  acidifying,  filtered 
off  and  ignited  in  a  porcelain  crucible  with  a  little  nitric 
acid,  yielding  Sb  O2,  containing  79.2  per  cent  of  Sb. 
The  sulphide  of  lead  remains  in  the  residue  after  treat- 
ing with  ammonium  sulphide.  It  is  dissolved  by  boil- 
ing with  nitric  acid  and  filtering  off  from  the  residue. 
The  filtrate  is  then  evaporated  with  H2  SO4  and  alcohol 
added,  when  sulphate  of  lead  separates. 

Zinc,  Cobalt,  and  Nickel.  A  basic  acetate  precipita- 
tion leaves  the  above-named  three  metals  in  the  filtrate. 
The  method  for  their  separation  thus  becomes  very 
much  simplified.  Pass  H2  S  through  the  filtrate  from 
the  basic  acetate  precipitation,  keeping  it  quite  warm. 
If  very  little  free  acetic  acid  be  present,  some  of  the 
Co  and  Ni  are  then  precipitated  along  with  the  Zn  S, 
which,  as  is  well  known,  is  precipitated  by  H2  S  even 
in  excess  of  acetic  acid.  By  treating  the  precipitated 
sulphides  with  warm  acetic  acid  all  the  Co  S  and  Ni  S 
may  be  extracted.  The  Zn  S  is  dissolved  in  H  Cl  and 
precipitated  with  sodium  carbonate  in  small  excess  at 
a  boiling  heat.  The  ignited  precipitate  from  this  is 
Zn  O,  containing  80.26  per  cent  of  zinc.  The  cobalt 
and  nickel  are  precipitated,  together  with  manganese, 
with  ammonium  sulphide.  The  Co  S  and  Ni  S  are 
freed  from  Mn  S  by  treating  with  cold  dilute  H  Cl 
(i  H  Cl,  1. 1 2  specific  gravity,  to  6  H2  O)  which  dis- 
solves out  the  Mn  S.  The  Co  S  and  Ni  S  are  then 
ignited  together  with  a  little  nitric  acid  and  ammo- 
nium carbonate.  The  cobalt  is  hereby  converted  into 


7O  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

metallic  cobalt,  and  the  nickel  into  protoxide  (Ni  O). 
A  separation  of  the  two  metals  is  entirely  unneces- 
sary, owing  to  the  small  amounts  present  of  either 
metal. 

Barium.  A  few  grams  of  ore  are  fused  with  sodium 
carbonate  and  the  mass  extracted  with  water  and  fil- 
tered. Any  barium  present  in  the  ore  is  thus  left  with 
the  residue  as  barium  carbonate.  The  residue  is  dis- 
solved in  H  Cl,  and  any  small  amount  of  silica  present 
separated  by  evaporation  to  dryness  in  the  usual  way. 
In  the  filtrate  from  the  silica  the  barium  is  precipitated 
with  H2  SO4  and  weighed  as  Ba  SO4,  containing  65.67 
per  cent  of  Ba  O. 

i.  Notes  on  the  Dry  Assay  of  Iron  Ores.  The 
dry  assay  of  iron  ores  is  but  little  practised  since  the 
comparative  perfection  of  the  analytical  methods  in  the 
wet  way,  but  it  is  still  occasionally  useful,  and  a  few 
directions  bearing  upon  the  same  may  be  here  in  place. 
The  aim  of  the  dry  assay  may  be  either  to  ascertain  the 
maximum  amount  of  iron  that  can  be  obtained  from  an 
ore,  in  which  case  many  fluxes  that  are  not  used  in  the 
blast-furnace  may  be  employed,  such  as  fluor-spar,  glass 
free  from  lead,  etc. ;  or  the  object  may  be  to  determine 
the  practical  working  of  an  ore  in  the  blast-furnace 
burden,  which  has  been  previously  calculated  from  re- 
sults of  analysis.  The  former  is  generally  the  aim  of 
the  operation.  When  using  fluor-spar  a  considerable 
amount  of  silicon  is  taken  up  by  the  reduced  metal. 
The  reaction  by  which  this  occurs  is  considered  to  be : 


ANALYSIS    OF    IRON    ORES.  7 1 

12  Ca  F12  +  4  Si  O2   =   4  Ca  Si  F16  +  8  Ca  O, 
and 

Ca  Si  F16  +  n  Fe  +  2  C  +  Si  O2   = '   Fe  n  Si  +  Ca  F12  +  F14  Si  +  2  CO. 

Fluor-spar  is  thus  apt  to  cause  too  favorable  results, 
and  must  be  used  with  caution.  The  best  way  of  testing 
an  unknown  ore  in  the  dry  way  is  to  weigh  out  say  five 
one-gram  samples  of  the  ore  into  five  numbered  char- 
coal-lined crucibles,  charging  each  sample  with  a  differ- 
ent proportion  of  quartz  and  carbonate  of  lime.  This 
is  the  old  well-tried  Swedish  method.  As  to  the  choice 
of  crucibles  and  furnace,  there  is  no  need  of  entering 
into  minute  descriptions  of  the  same,  as  all  dealers  in 
chemists'  supplies  can  furnish  apparatus  of  this  kind. 
The  mixtures  of  ores  and  fluxes  are  put  into  the  char- 
coal-lined crucibles,  a  little  flux  being  put  separately 
on  top,  in  order  to  wash  down  any  globules  of  metal 
from  the  sides  of  the  crucibles  during  fusion.  A  piece 
of  charcoal  is  placed  on  top  of  each  crucible,  and  the 
fusion  proceeded  with  in  a  wind-furnace  or,  better  still, 
in  a  "  Sefstroms  "  furnace.  Whatever  kind  of  furnace 
be  used,  the  heat  should  be  raised  gradually,  say  in 
three  stages,  so  that  the  operation  be  completed  in  one 
and  a  quarter  hours.  The  first  raise  of  heat  may  be 
made  after  half  an  hour,  then  after  five  minutes  another 
slight  raise.  After  ten  minutes  more  full  heat  is  ap- 
plied for  about  twenty  minutes.  The  crucibles  are  then 
taken  out  and  their  contents,  after  cooling,  emptied  on 
to  watch-glasses.  The  buttons  of  metallic  iron  are 
weighed,  and  any  globules  contained  in  the  slag  ex- 


72  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

tracted  with  a  magnet  and  weight  added.  The  slag  is 
also  examined;  the  principal  observations  to  be  made 
are  whether  it  seems  well  fused  and  separated  from 
the  iron,  and  whether  it  has  a  stony  or  glassy  fracture, 
etc.  (more  or  less  basic  or  acid).  No  very  positive  con- 
clusions, however,  can  be  drawn  from  the  colors  of 
these  crucible-slags. 

B.  —  Analysis  of  Slags,  Limestones,  etc. 

Slags  may  be  analyzed  according  to  the  directions 
given  for  iron  ores,  with  very  few  modifications.  All 
slags  contain  silica  in  varying  proportions.  Blast-fur- 
nace slags  contain  25  to  65  per  cent,  Bessemer  and 
open  hearth  slags  12  to  55  per  cent,  puddling  and  sim- 
ilar slags  5  to  35  per  cent  of  silica.  Blast-furnace  slags 
contain  as  bases  chiefly  calcium,  magnesium  and  alu- 
minium, whilst  the  other  slags  contain  mostly  iron  and 
manganese.  Slags  from  coke  blast-furnaces  contain 
much  sulphur  as  calcium  sulphide.  Such  slags  can 
often  be  completely  decomposed  by  H  Cl,  and  the  sul- 
phur in  them  then  determined  by  the  bromine  method 
exactly  as  in  steel.  Phosphorus  rarely  occurs  in  blast- 
furnace slags.  So-called  basic  slags,  which  are  chiefly 
produced  by  the  Thomas'  basic  Bessemer  process,  con- 
tain up  to  30  per  cent  of  phosphoric  acid.  The  deter- 
mination of  phosphorus  in  such  slags  is  of  importance. 
Such  determinations  are,  however,  rendered  somewhat 
difficult  by  the  large  amount  of  phosphorus  present. 
The  following  method  can  be  recommended. 


ANALYSIS  OF  COAL  AND  COKE.  73 

Weigh  out  about  one  gram  of  the  finely  ground  slag 
and  fuse  with  sodium  carbonate  in  a  platinum  crucible. 
Separate  the  silica  as  described  in  the  case  of  iron  ores, 
and  make  a  basic  acetate  separation  in  the  filtrate.  The 
basic  acetate  precipitate  is  dissolved  in  H  Cl  and  boiled 
down  with  H  NO3  to  remove  H  Cl  and  acetic  acid. 
The  solution  is  then  diluted  to  say  half  a  litre.  From 
this  volume  aliquot  portions  are  measured  off  and  the 
phosphorus  determined  with  molybdic  acid  and  mag- 
nesia mixture  as  usual. 

Limestones  and  other  fluxes  are  easily  analyzed  ac- 
cording to  the  same  methods  that  are  used  for  ores,  etc. 
Some  judgment  is  required  in  weighing  out  a  suitable 
quantity  of  sample,  so  as  not  to  obtain  too  bulky  pre- 
cipitates. 

C.  —  Analysis  of  Coal  and  Coke. 

Complete  analysis  of  fuel  is  seldom  required  in  prac- 
tice. When,  however,  such  analyses  have  to  be  made, 
the  platinum  apparatus  for  carbon  determination  in 
iron  and  steel  in  combination  with  the  platinum-tube 
used  in  gas  analysis  —  vide  below  —  may  be  conven- 
iently used. 

In  practice  the  determinations  most  frequently  made 
in  fuels  are :  moisture,  volatile  matter,  fixed  carbon,  ash, 
phosphorus  and  sulphur. 

(a)  Determination  of  Moisture,  Volatile  Matter,  Fixed 
Carbon  and  Ash.  Two  grams  of  powdered  sample  are 
dried  in  a  weighed  platinum  crucible  at  120°  C.  for 
one  hour.  The  loss  of  weight  gives  the  moisture. 


74  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

The  crucible  is  then  heated,  with  the  lid  on,  in  the 
flame  of  a  Bunsen's  burner,  letting  the  flame  completely 
surround  the  crucible.  The  lid  should  fit  tightly.  The 
loss  of  weight  gives  the  volatile  matter.  During  this 
heating  some  of  the  escaping  hydrocarbons  suffer  dis- 
sociation and  deposit  carbon  as  a  coating  on  the  sides 
of  the  crucible  and  on  the  under  side  of  the  lid.  When 
no  more  flames  appear  around  the  edges  of  the  lid  all 
the  volatile  matter  may  be  considered  as  expelled.  The 
fixed  carbon  is  then  burnt  off  with  the  aid  of  a  slow 
current  of  oxygen,  which  is  thrown  upon  the  heated 
mass  through  the  stem  of  a  clay  tobacco  pipe.  The 
loss  of  weight  gives  the  fixed  carbon,  the  ash  being 
obtained  at  the  same  time.  The  ash  may  now  be  fused 
and  analyzed  as  an  iron  ore  or  slag. 

(b)  Determination  of  Phosphorus.     The  phosphorus 
may  be  determined  in  the  ash  by  fusing  the  same  with 
carbonate  of  soda,  as  described  heretofore. 

(c)  Determination  of  Sulphur.     "  Eschkas    method." 
Two  grams  of  the  powdered  sample  are  mixed  with  3 
to  4  grams  of  a  mixture  of  2  parts  of  strongly  calcined 
magnesia  and   i   part  of  carbonate  of  soda,  and  heated 
for  about  one  hour  in  an  open  platinum  crucible,  with 
frequent   stirring   with    a    platinum   wire.      The    light, 
flocculent  magnesia  causes  a  rapid  combustion,  and  the 
sulphur  enters    into   combination  with  sodium    as    sul- 
phate, sulphite,  sulphide,  etc.     When  all  the  carbon  is 
burnt  out,  the  contents  of  the  crucible  is  thrown  into 
a  beaker  containing  hot  water.     The  magnesia  is  filtered 


ANALYSIS  OF  COAL  AND  COKE.  75 

off  and  washed  with  hot  water.  Some  bromine  water 
is  now  added  to  the  filtrate  from  the  magnesia,  in  order 
to  convert  all  the  sulphur  into  H2  SO4.  The  filtrate  is 
acidified  with  H  Cl,  some  Ba  C12  added  and  the  bromine 
boiled  off.  The  barium  sulphate  is  then  filtered  off  and 
determined  as  usual. 


CHAPTER   IV. 

NOTES    ON    GAS    ANALYSIS. 

BLAST-FURNACE  gases  are  chiefly  analyzed  with  the 
view  of  ascertaining  the  relative  quantities  of  CO2  and 
CO,  as  an  index  of  the  good  or  bad  working  of  the  fur- 
nace, while  the  composition  of  gas-producer  gases  is 
usually  desired  in  order  to  ascertain  their  heating  power. 
The  following  is  a  convenient  method  for  the  complete 
volumetric  analysis  of  gases,  as  they  occur  in  iron  and 
steel  manufacture. 

a.  Collection  of  Gases.  A  sample  of  gas  may  be 
collected  by  means  of  a  rubber  bag  (supplied  for  the 
purpose  by  chemical  dealers),  from  which  the  air  has 
been  previously  exhausted  by  means  of  the  suction 
pump.  A  rubber  bag  is  not  suitable  when  the  sample 
of  gas  has  to  be  preserved  for  any  length  of  time.  The 
arrangement  shown  (Fig.  VIII.)  is  then  to  be  recom- 
mended. The  gas  here  passes  up  through  the  funnel 
F  and  the  rubber-tubing  with  the  glass  tube  K,  filled 
with  asbestos  for  retaining  dust.  A  saturated  solution 
of  common  salt,  Na  Cl,  should  be  used  to  fill  the  two 
bottles.  Such  a  solution  does  not  absorb  any  gas,  whilst 
pure  water  absorbs  carbonic  acid  in  considerable  quan- 


NOTES    ON    GAS    ANALYSIS.  77 

tity.  According  to  Bunsen,  the  following  gas  volumes 
(at  o°  C.  and  760  millimetres)  are  absorbed  by  one  volume 
of  air-free  water  at  1 5°,  on  shaking :  — 

Oxygen          .        *        .  .  (O)  ....  .030 

Nitrogen        .         .         .  .  (N)  .  *         .      •  ^ "..        .015 

Carbonic  oxide      .         .  .  (CO)  .  .         .         .           .024 

Hydrogen      ....  (H)  .  .         *        <.'.;        .019 

Marsh  gas     .         .         .  .  (CH4)  .  .         »         .  .C       .039 

Olefiantgas.         .         .  .  (C2  H4)  .  .     L.        .           .161 

Carbonic  acid        .         .  .  (CO2)  -.;  .         .         .':''"     1.002 

Sulphuretted  hydrogen  .  .  (H2  S)  .  v  •  -.'.'•«•    .•         3.300 

Sulphurous  acid     .      '.  ^  (SO2)  /  .  .        ;>,     .       45.000 

Ammonia      .     .'•';       >  .  (H8  N)  ,v  .    ."••'.      .     727.000 

Hydrochloric  acid        ,.  .  (H  Cl)  *  *         *         .     458.000 

With  increase  of  temperature  the  absorbing  power 
of  water  is  diminished.  In  the  following  method  use  is 
made  of  water  for  measuring  the  gases,  but  as  there  is 
no  shaking,  and  the  whole  analysis  is  completed  in 
little  more  than  one  hour,  no  considerable  error  can 
ensue  from  the  absorbing  influence  of  the  water. 
When  collecting  the  gas  care  should  be  taken  that  the 
sample  obtained  be  a  fair  average  representing  the  gas 
to  be  examined ;  thus  in  some  cases,  where  the  gas  is 
suspected  of  being  irregularly  mixed  in  the  flue,  etc., 
the  sample  should  be  taken  from  a  tube  full  of  small 
holes  stretching  across  the  whole  flue  through  which 
the  gas  is  passing. 

6.  The  Gases  to  be  Determined  are  CO2,  O,  C2H4, 
CO,  H,  and  CH4.  The  nitrogen  is  taken  by  difference. 


NOTES    ON    THE    CHEMISTRY    OF    IRON. 


Besides  these  gases  the  gas-mixture  may  contain  small 
quantities  of  SO2,  H2  S,  etc.  The  gas-mixture  may 
also  contain  much  steam,  when  coming  hot  from  the 
furnaces.  This  steam  may  be  estimated  by  passing  a 
quantity  of  the  hot  gas  through  a  weighed  chloride  of 

calcium  tube,  and  measur- 
ing the  volume  of  gas  thus 
passed  through.  The  chlo- 
ride of  calcium  tube  may 
be  inserted  between  the  as- 
bestos tube  K  and  the  water 
bottle  (Fig.  VI 1 1).  TheH2S 
and  SO2  cannot  be  deter- 
mined over  water.  In  this 
case  mercury  tubes  must  be 
used.  A  solution  of  3  grams 
of  iodine  -f-  4-5  grams  of 
iodide  of  potash  in  50  cubic 
centimetres  of  water  can  be 
used  for  absorbing  these 
gases.  The  SO2  is  thereby 
oxidized  to  H2  SO4,  and  the  H2  S  is  converted  into  2 
HI,  with  separation  of  sulphur;  the  iodine  solution 
hereby  loses  its  brown  color. 

Fig.  IX.  shows  the  apparatus  for  determining  the 
ordinary  ingredients  in  the  gases  in  question.  The 
burettes  B  and  B^  of  100  cubic  centimetres  capacity, 
are  graduated  into  TV  cubic  centimetres.  B  has  a  fun- 
nel at  the  upper  end ;  between  this  funnel  and  B  there 


NOTES    ON    GAS    ANALYSIS. 


79 


is  a  glass  stop-cock  with  two  perforations  so  arranged 
that  B  can  be  connected  either  with  the  funnel  or  with 


J8i  and  the  platinum  tube  P.1     The  latter  consists  of  a 
tube  with  one-half  millimetre  internal  diameter,  twisted 

1  J.  Bishop,  of  Malvern  Station,  Sugartown,  Chester  County,  Penn.,  supplies 
all  the  platinum  apparatus  recommended  in  this  book. 


8O  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

into  a  single  coil  and  provided  with  small  cylinders  of 
German-silver  at  the  ends  ;  to  these  cylinders  the  rubber- 
tubings  can  be  securely  attached.  The  lower  end  of  B 
is  connected  with  the  water-bottle  A  and  the  suction- 
bottle  S  by  means  of  a  three-way  glass-tube.  The  air  in 
61  is  kept  rarified  by  means  of  the  suction-pump,  so  that 
liquid  can  be  drawn  from  B,  even  when  the  stop-cock  at 
the  upper  end  is  closed.  Between  B  and  the  three-way 
tube  is  a  one-way  glass  stop-cock,  and  between  the  three- 
way  tube  and  A 'and  S  are  pinch-cocks.  The  remainder 
of  the  apparatus  is  easily  understood  from  the  sketch. 

A  sample  of  gas  is  taken  into  B  through  the  neck  of 
the  funnel  by  means  of  a  glass  tube,  to  the  end  of  which 
a  piece  of  rubber-tubing  has  been  attached.  The  glass 
tube  can  thus  be  pressed  tightly  into  the  neck  of  the 
funnel.  The  burette  being  previously  filled  with  water, 
the  gas  is  drawn  into  the  same  by  lowering  the  flask  A. 
The  volume  of  the  gas  thus  drawn  in  is  then  read  off 
by  closing  the  stop-cock  at  the  lower  end  of  B,  leaving 
the  funnel  connected  with  B.  The  ends  of  B  and  the 
funnel  should  have  very  narrow  apertures.  A  file-mark 
is  made  on  the  funnel  about  60  millimetres  above  the 
stop-cock,  and  the  funnel  is  always  kept  filled  with  water 
up  to  this  file-mark  when  reading  off.  It  is  well  to  have 
the  gas  a  little  compressed,  so  that  i  cubic  centimetre 
or  so  will  bubble  out  through  the  water  in  the  funnel. 
The  volume  of  gas  should  be  read  off  by  the  lower  part 
of  the  "  meniscus,"  or  water-surface.  The  temperature 
is  noted,  and  correction  is  made  for  the  amount  of  aque- 


NOTES    ON    GAS    ANALYSIS.  8 1 

ous  vapor  corresponding  to  said  temperature  as  follows. 
Suppose  the  temperature  be  15°,  and  the  pressure  760 
millimetres.  From  the  tension-tables  for  aqueous  vapor 
(vide  Thorpe,  "  Quantitative  Analysis,"  or  Bailey,  "  Chem- 
ists' Pocket-book ")  we  find  the  corresponding  tension 
to  be  12.690  millimetres  mercury.  Now  i  cubic  metre 
of  aqueous  vapor,  according  to  Bunsen,  at  o°  and  760 
millimetres  weighs  .8048  kilos.  Thus  we  have : 

760  :  12.699  —  .8048  :  x  '.'  x  =  .0135  kilos. 

By  volume  this  is  : 

.8048  :  1000  =  .0135  :  x  v  x  —  16.77  liters  at  o°,  or  at  15°  =  16.77 
(i  +  .004  x  15)  =  17.78  liters,  or  in  100  cubic  centimetres  of  gas 
(the  quantity  generally  used  for  analysis)  1.778  cubic  centimetres. 

At  20°  the  tension  of  aqueous  vapor  is  17.391  milli- 
metres, and  its  volume  in  100  cubic  centimetres  of 
gas  =  2.40  cubic  centimetres.  Therefore  if  TOO  cubic 
centimetres  were  originally  measured  off,  the  actual 
volume  of  dry  gas  would  in  this  case  be  only  97.6 
cubic  centimetres.  The  temperature  should  be  observed 
in  the  subsequent  operations  throughout,  as  the  gas  ex- 
pands according  to  the  formula  v  (i  -f-  .004  f\  or  about 
.4  cubic  centimetres  for  every  degree  Centigrade. 

c.  Determination  of  Carbonic  Acid.  The  ingre- 
dients of  the  gases  must  be  determined  in  the  order  de- 
scribed, as  some  of  the  reagents  used  for  their  absorption 
would  otherwise  absorb  more  than  one  gas. 

For  the  removal  of  CO2  is  used  a  solution  of  16 
grams  of  potassium  hydrate  in  100  cubic  centimetres 


82  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

of  water.  Four  or  five  cubic  centimetres  of  this  solu- 
tion absorb  100  cubic  centimetres  of  CO2.  Draw  out 
a  few  cubic  centimetres  of  water  by  means  of  the  suc- 
tion bottle,  taking  care  to  have  the  funnel  shut  off 
when  the  lower  stop-cock  is  open.  Let  a  few  cubic 
centimetres  of  the  potassium  hydrate  solution  Mow  into 
the  burette  from  the  funnel.  All  the  CO2  is  absorbed 
when  the  alkaline  liquid  flows  down  slowly  along  the 
sides  of  the  burette.  The  potassium  hydrate  is  then 
carefully  washed  out  by  repeatedly  drawing  off  the 
liquid  from  the  bottom  of  B  by  means  of  suction,  and 
letting  pure  water  flow  in  from  the  top  of  the  burette ; 
the  remaining  volume  of  gas  is  then  read  off. 

d.  Determination  of  Oxygen.     The   absorption    of 
the  oxygen  is  effected  by  means  of  pyrogallate  of  pot- 
ash.    Twenty  grams  of  pyrogallic  acid  (a  light,  white 
powder ;  must  be  kept  in  darkened  bottles)  are  dissolved 
in  100  cubic  centimetres  of  air-free  water.     This  solu- 
tion  is   mixed,  immediately  before  use,  with  its  equal 
volume  of  the  above  K  O  H  solution.     Two  cubic  cen- 
timetres of  this  solution  absorb  the  oxygen  in  100  cubic 
centimetres  of  air. 

e.  Determination  of  Ethylene  (C2  H4).     Ethylene 
decomposes  at  a  high  heat  into  carbon  and  marsh  gas 
(CH4),  and  does  not  generally  occur  in    blast-furnace 
gases,  nor  in  producer-gases  from  coke.     Producer-gases 
from  bituminous  fuel  may  contain  as  much  as  two  per 
cent  of  Ca  H4. 

Fuming  sulphuric  acid  (Ha  S2  O7),  as  well  as  bromine, 


NOTKS    ON    (IAS    ANALYSIS.  83 

(In*  hydrocarbons  of  the  C2  H4  series ;  bromine 
is  the  more  convenient  reagent  to  use.  Caution  must  be 
observed  in  tin's  ease,  as  thr  bromine  vapor  has  .1  i-jvai 
tension.  One  hundredth  of  a  <;rain  of  bromine  absorbs 
about  one  cubic  centimetre  of  Ca  H4,  forming  ethyl- 
bromide.  Water  shaken  up  with  bromine  contains  .02 
to  .03  grams  of  bromine  per  cubic  centimetre.  A  very 
small  amount  of  bromine  water  is  consequently  required 
for  the  absorption  of  ethylene.  The  ethyl-bromide  ap- 
pears in  oily  drops  on  the  sides  of  the  burette,  when 
ethylene  is  present. 

/  Determimilioii  of  Carbonic  Oxide.  The  CO 
is  absorbed  by  means  of  a  solution  of  15  grams  of 
Cu2  O  (sub-oxide  or  red  oxide  of  copper)  in  100  cubic 
centimetres  of  H  Cl,  1.19  specific  gravity.  The  solu- 
tion is  prepared  by  adding  the  Cu2  O  to  the  H  Cl  at 
7o°-8o°  temperature,  and  allowing  a  little  paraffin  to 
melt  on  the  surface,  to  prevent  oxidization.  One  cubic 
centimetre  of  the  fresh  sub-chloride  of  copper  solution 
absorbs  about  20  cubic  centimetres  of  CO.  It  is  sup- 
posed that  the  compound  2  Cu  Cl  -f~  CO  is  hereby 
formed.  In  washing  out  the  sub-chloride  of  copper 
some  dilute  H  Cl  must  first  be  used,  to  prevent  the 
separation  of  the  white  chloride. 

g.  Determination  of  Hydrogen  and  Marsh  Oas. 
After  removing  the  above  gases,  about  20  cubic  centi- 
metres of  pure  oxygen  are  taken  into  B,  the  gas  having 
been  previously  transferred  to  B^  through  P,  by  means 
of  the  bottles  A  and  A±.  The  gas  is  then  brought  back 


84  NOTES    ON    THE    CHEMISTRY    OF    IRON. 

into  B\,  and  the  total  volume  read  off.  Twenty  cubic 
centimetres  of  oxygen  is  an  ample  quantity  for  the  gases 
in  question.  As  a  safeguard  against  explosions,  the 
rule  may  be  observed,  that  the  sum  of  the  volumes  of 
the  gases  taking  par i  in  the  combustion  must  not  exceed 
one-half  of  the  total  volume  of  gases  in  the  burette. 
The  platinum  coil  is  now  heated  to  redness  by  means 
of  a  small  Bunsen  burner,  whilst  the  gas  is  passed  from 
B  to  B\,  and  again  from  B\  to  B.  Complete  combustion 
of  hydrogen  and  marsh  gas  then  takes  place  in  the 
tube.  Vapor  of  water,  which  condenses,  and  carbonic 
acid  are  formed,  one  volume  of  hydrogen  giving  one 
volume  of  water,  and  one  volume  of  marsh  gas  giving 
two  volumes  of  water  and  one  volume  of  carbonic  acid, 
according  to  the  following  formulas : 

2  H  O          H2O. 

2  VOl.  I   VOl.  2    VOl. 

CH4  4Q     =    C02          2  H20. 

2  vol.         4  vol.         2  vol.  4  vol. 

The  actual  number  of  cubic  centimetres,  representing 
the  free  hydrogen  in  the  original  gas  volume,  is  conse- 
quently obtained  from  the  formula, 

Hydrogen  =  §  [M  -  2  G], 

M  being  the  total  diminution  of  volume  after  combus- 
tion, and  G  the  volume  of  carbonic  acid  from  the  marsh 
gas.  This  carbonic  acid  is  determined  as  previously 
described,  giving  the  volume  of  marsh  gas  direct. 


NOTES  ON   GAS   ANALYSIS.  85 

k.  Notes  on  Products  of  Combustion  (Eggertz). 
When  fuel  is  properly  burnt  the  escaping  products  of 
combustion  should  not  contain  any  combustible  gases 
such  as  hydrocarbons,  hydrogen  or  carbonic  oxide,  but 
only  carbonic  acid,  nitrogen,  oxygen  and  steam.  To 
obtain  this  result  a  certain  excess  of  air  is  generally 
required,  but  too  great  an  excess  must  be  avoided,  as 
otherwise  heat  is  carried  away  uselessly.  As  a  rule  it 
is  supposed  that  the  excess  of  air  should  be  equal  to 
the  theoretical  or  calculated  amount  of  air  necessary  for 
complete  combustion. 

The  actual  excess  of  air  in  each  separate  case  can  be 
estimated  by  determining  the  amount  of  carbonic  acid 
present  in  the  products  of  combustion.  Experiments 
made  in  Munich*  have  shown  that  the  following  figures 
give  the  relation  between  the  excess  of  air  used  and  the 
carbonic  acid  present  with  the  products  of  combustion  : 

4  per  cent  CO2      .     .     .     4.6  times  the  theoretical  air  quantity. 


6       "  "       .     .     .     3- 


it          it  (I  tt  tt 

tt  tt  H  tt  It 


it  II  tt  tt  it  tt  « 

U  H  2>  «  ><  «  «  « 

"  "  " 

«  «  « 


^  (t  U  -          «  tt  t(  (I  « 

o  it  II 

10 

- 
^  «  «  Q       «  «  «  «  « 

The  carbonic  acid  occupies  the  same  volume  as  the 
oxygen  that  enters  into  the  same  ;  but  oxygen  has  also 

*  Bayrisches  Industrie  und  Gewerbeblatt,  1880. 


86  NOTES   ON   THE   CHEMISTRY   OF   IRON. 

been  consumed  for  the  combustion  of  hydrogen,  hydro- 
carbons and  sulphur. 

The  best  result  in  the  above  experiments  was  ob- 
tained when  the  gases  contained  10  per  cent,  of  CO2, 
corresponding  to  1.7  times  the  theoretical  amount  of 
air.  The  loss  of  heat  through  the  combustion  products 
hereby  went  down  to  10  per  cent,  whereas  with  4  per 
cent  CO2  the  loss  thus  incurred  was  36  per  cent,  and 
with  8  per  cent  CO2  18  per  cent.  If  the  CO2  exceeds 
10  per  cent  it  is  to  be  feared  that  some  combustible 
gases  may  yet  be  present  in  the  escaping  gases.  In  the 
best  cases  these  contain  only  i  per  cent,  of  CO  and  H, 
but  in  bad  cases  as  much  as  3  per  cent.  CO  and  i  per 
cent  H,  or  more. 

For  the  combustion  of  i  kg.  of  pure  carbon  to  car- 
bonic acid  are  required  2.67  kg.  oxygen  or  11.56  kg. 
air.  If,  as  usual,  we  assume  that  at  least  the  double 
theoretical  amount  be  required  for  complete  combus- 
tion, i  kg.  of  pure  carbon  will  require  23  kg.  or  18  cubic 
metres  of  air. 

For  measuring  the  amount  of  air  rushing  into  a 
furnace  use  is  made  of  anemometers,  obtainable  from 
scientific  instrument  makers. 

The  loss  of  heat  caused  by  the  products  of  combus- 
tion is  due  to  three  circumstances  :  ist,  incomplete  com- 
bustion of  the  fuel,  so  that  combustible  gases  escape ; 
2d,  the  amount  and  the  temperature  of  the  products  of 
combustion  ;  and  3d,  the  accompanying  steam.  . 

To  calculate  these  losses  we  make  use  of  the  table 


NOTES   ON   GAS  ANALYSIS.  87 

on  p.  87.  The  specific  heats  per  cubic  metre  of  air, 
oxygen,  hydrogen,  nitrogen  and  carbonic  oxide  are  in 
these  calculations  considered  identical  and  expressed  by 
the  number,  .307. 

Example.     Chimney  gas,  temp.  —  210°  C. 

Carbonic  acid     =12.5  per  cent. 
Carbonic  oxide  =     2.3 
Hydrogen  =     i.o 

Oxygen  =    4.2 

Nitrogen  =  80.0 

100.0  volumes. 

One  hundred  cubic  metres  of  this  gas  are  accom- 
panied by  8  kg.  of  water  as  steam. 

The  combustible  gases  consist  of  CO  and  H,  and 
these  are  capable  of  developing  : 

2.3  x  3007  +  i.o  x  2655 =  9,571  h.  u. 

with  100  c.  m.  of  gas  at  210°  C.  are  carried  off  (2.3  + 

i.o  4-  4.2  +  80.0)  .307  x  210  +12.5  x  .4256  x  210  =  6,758  h.  u. 
8  kg.  water  as  steam  occupy  a  volume  of  8  :  .8048  = 

9.940  c.  m.,  and  this  carries  off  9.940  x  .3823  x  210  =  798  h.  u. 

Total  loss  of  heat  17,127  h.  u. 

This  heat  can  be  produced  by  the  combustion  of 
VoW  =2.12  kg.  pure  carbon. 

In  100  c.  m.  gas  are  contained  (12.5  +  2.3)  x  .5363 
=  7.94  kg.  pure  carbon.  Thus  of  the  7.94  kg.  pure 
carbon  in  the  fuel,  2.12  kg.,  or  26.94  Per  cent,  have  been 
lost. 


88  NOTES   ON   THE  CHEMISTRY   OF  IRON. 

i.  Calculation  of  the  amount  of  Air  blown  into  a 
Blast  Furnace  (Stockmann,  Beckert). 

Example  :  A  blast  furnace  produces  daily  40  tons  of 
pig-iron  with  4  per  cent  carbon,  using  1.3  tons  coke 
per  ton  pig-iron.  The  coke  contains  77  per  cent  car- 
bon ;  the  ores  are  free  from  carbonic  acid  ;  the  lime- 
stone (48  tons)  has  43  per  cent  CO3  =  11.73  Per  cent 
C.  The  furnace  consequently  received 

with  the  coke,          40  x  1.3  x  .77=  40.040  tons  carbon 
with  the  limestone,  48  X  .  1 1 73         =    5.630     "         " 

total  45.670     " 

The  pig-iron  contains  40  X  .04  =     1.600     "         " 
Consequently  are  volatilized,  44.070     "       .  " 

or  per  minute  30.60  kg. 

The  escaping  blast-furnace  gas  contains  : 

Vol.  %.  Weight  *. 

Nitrogen     .     .....     55.76  .     .    .    +    .  54.79 

Carbonic  acid      .     .       9.99 15-42 

Carbonic  oxide    .     .     24.88 24.45 

Marsh  gas 40 22 

Hydrogen   ....         .97 .07 

Steam 8.00 5.05 

100.00  vol.  per  cent.  100.00  weight  per  cent. 

This  gas  contains  in  the  CO2  4.21  per  cent,  in  the 
CO  10.48  per  cent,  in  the  CH4  .17  percent,  total  14.86 
weight  per  cent  of  carbon  ;  consequently  the  carbon 
in  the  gas  is  to  the  nitrogen  as  14.86  to  54.79.  With 
the  30.6  kg.  of  volatilized  carbon  112.8  kg.  of  nitrogen 


NOTES  ON  GAS  ANALYSIS.  89 

consequently  leave  the  furnace  per  minute,  correspond- 
ing to  146.85  kg.  or  113.57  cubic  metres  of  air. 

Another  ready  way  of  calculating  the  air  is  given  by 
Ledebur.  If  A  be  the  consumption  of  fuel  per  24 
hours,  p  the  amount  of  carbon  per  kg.  of  fuel,  and  Q 
the  consumption  of  air  per  minute,  we  have 

Ap 

O  =  —  —  cubic  metres. 
320 

This  formula  must  by  multiplied  by  a  coefficient  .75 
to  .85  to  correct  for  errors.  The  more  difficultly  reduci- 
ble the  ores  are  the  smaller  need  the  coefficient  be. 

We  can  also  calculate  the  amount  of  gas  leaving  the 
blast  furnace  in  the  same  way  as  the  incoming  air.  In 
the  above  example  we  find  that  for  every  kg.  of  gaseous 
carbon  .705  kg.  are  present  as  CO,  and  that  30.6  kg.  of 
carbon  leave  the  furnace  per  minute.  Out  of  these 
30.6  kg.  21.573  kg.  consequently  leave  the  furnace  as 
CO,  weight  about  50.3  kg.  =  40.23  c.  m.  With  24.88 
per  cent  CO  by  volume  in  the  gases,  we  thus  readily 
find  that  162  cubic  metres  of  gas  leave  the  furnace  per 
minute. 

/.  Calculation  of  the  amount  of  Carbon  used  for 
direct  and  indirect  reduction  in  the  Blast  Furnace 

CO 

from  the  relation  between  CO2  and  CO  ;  ^^r  by  vol. 

CO 

CO 
=  k  ;    ~  by  weight  —  m  =  1.57  k. 


Whatever  degree  of  oxidation   the  iron  may  possess 
in  the   ore  when  charged  on  the  blast  furnace,  it  will 


QO  NOTES   ON  THE   CHEMISTRY   OF  IRON. 

ultimately  arrive  at  the  lowest  degree,  Fe  O,  before  being 
reduced  to  metallic  iron.  The  Fe  O  does  not  rapidly 
give  up  its  oxygen  except  at  a  very  high  temperature,  at 
the  same  time  absorbing  per  unit  iron  the  same  number 
of  heat  units  as  are  set  free  when  the  same  unit  of  iron 
combines  with  oxygen  to  form  Fe  O.  At  the  high  tem- 
perature at  which  the  reduction  of  Fe  O  takes  place 
rapidly  the  stability  of  CO2  is  exceedingly  small,  and 
even  if  the  reduction  at  first  take  place  with  CO  : 

Fe  O  +  CO  =  Fe  +  CO2, 

the  CO2  formed  would  take  up  carbon  and  form  CO, 
thus  :  CO2  +  C  —  2  CO,  which  means  loss  of  heat  and 
waste  of  carbon  in  the  blast  furnace,  since  the  heat  gen- 
erated by  the  oxidation  of  the  carbon  is  much  less  than 
the  heat  absorbed  by  the  reduction  of  Fe  O.  Thus  the 
reduction  by  carbon  direct,  either  : 

Fe  O  +  C  =  Fe  +  CO, 

or 

Fe  O  +  CO  +  C  =  Fe  +  2  CO, 

must  be  avoided.  In  order  to  accomplish  this  the 
stability  of  the  CO2  generated  by  the  reduction  with  CO 
must  be  insured  by  injecting  a  sufficient  excess  of  air. 
The  oxygen  in  this  air  forms  CO,  part  of  which  reduces 
the  Fe  O,  the  remaining  part  protecting  the  CO2  formed 
from  being  decomposed.  The  gas  mixture  then  ascends 
up  through  the  furnace,  meeting  the  mixture  of  ore, 
fluxes  and  fuel,  thereby  giving  off  its  heat  and  reducing 
the  ores,  etc. 


NOTES   ON   GAS  ANALYSIS.  91 

Professor  Akerman  has  made  experiments  on  the  re- 
duction of  ores  by  various  gas  mixtures,  according  to 
which  carbonic  oxide  must  not  be  mixed  with  more  than 
half  its  volume  of  carbonic  acid,  to  obtain  a  strongly  re- 
ducing action  on  Fe  O  at  a  temperature  of  8oo°-9OO°. 

Thus  the  following  formula  would  indicate  the  mini- 
mum amount  of  carbon  requisite  for  reduction  : 

3  CO  +  Fe  O  =  2  CO  +  CO2  +  Fe, 

or  per  atom  iron  3  atoms  of  carbon  (3x12  parts  by 
weight  of  carbon  per  56  p.  b.  u.  of  iron).  If  the  gas 
mixture  thus  generated  meets  Fe3  O4  higher  up  in  the 
furnace,  this  reaction  would  then  take  place  : 

6  CO  +  3  CO2  +  Fe3  O,  =  5  CO  +  4  CO2  +  3  Fe  O, 

and  if  this  gas  mixture  meet  Fe2  O3  still  higher  up  in  the 
furnace,  the  reaction  would  be  : 

10  CO  +  8  CO2  +  3  Fe2  O3  =  9  CO  +  9  CO2  +  2  Fe3  O4, 

the  gases  finally  leaving  the  furnace  with  equal  volumes 
of  CO  and  CO2.  For  reducing  one  weight  of  iron  the 
minimum  amount  of  carbon  required  would  thus  be  .643 
weights.  In  reality  many  blast  furnaces  show  less  con- 
sumption of  carbon  than  that,  even  with  more  CO  in 
the  gases  than  as  per  above  formulas.  This  can  be  ex- 
plained by  the  fact  that  there  is  a  surplus  of  heat  in  the 
blast  furnace,  partly  generated  in  the  furnace  and  partly 
introduced  with  the  heated  blast.  This  surplus  of  heat 
covers  the  loss  caused  by  direct  reduction,  thus  effecting 
a  saving  of  coal. 


92  NOTES   ON   THE   CHEMISTRY   OF   IRON. 

It  should  be  borne  in  mind  that  the  chemical  reactions 
which  take  place  in  the  blast  furnace  are  nearly  all  more 
or  less  interwoven,  forming  no  distinctly  defined  stages, 
as  would  seem  from  the  above  formulas. 

Thus  the  CO2  formed  by  the  reduction  of  iron  oxides 
will  give  off  oxygen  to  carbon  more  or  less  through  the 
whole  furnace.  Such  is  the  disadvantage  considered  to 
be  derived  from  this  fact  that  it  has  been  proposed  to 
separate  the  fuel  and  the  ore  in  the  blast  furnace,  not 
allowing  them  to  meet  until  carbonization  is  to  take 
place. 

In  calculating  the  amount  of  carbon  used  for  direct 
reduction  we  must  deduct  the  CO2  from  ores  and  fluxes. 
Another  source  of  error  is  the  dissociation  of  CO,  which 
takes  place  in  the  upper  part  of  the  furnace :  2  CO  =  C 
+  CO2. 

If  the  ore  used  be  Fe3  O4,  the  relation  between  CO2  : 
CO  =  m  should  be  1.25,  and  if  the  ore  be  Fe2  O3,  m 
should  be  1.57,  for  complete  indirect  reduction,  accord- 
ing to  Prof.  Akerman's  formulas. 

m.  Notes  on  Heat  Calculations.  In  the  appendices 
are  given  tables  for  facilitating  the  calculation  of  the 
calorific  power  and  theoretical  temperature  of  gases  ; 
supposing  the  gases  to  be  all  of  o°C.  and  760  m.  m. 
pressure,  according  to  the  formula  : 

W  =  T  (combustion  products  x  their  resp.  spec,  heats). 

If  the  gas  had  an  initial  temperature  /,  the  formula 
would  be 


NOTES  ON  GAS  ANALYSIS. 


93 


W  -+•  (ingredients  of  gas  x  their  resp.  spec,  heats)  /  =  T  (combustion 
products  x  their  resp.  spec,  heats). 

The  theoretical  temperatures  are  of  course  never  at- 
tained in  practice  owing  to  dissociation  and  other  causes, 
but  they  are  of  value  for  comparing  different  gases,  etc. 

For  solid  fuel  we  have  the  formulas  : 
80.8  x  C  +  344.6  H  (Scheurer  Kastner)  and  80.8  x  C  +  344.6  x 

(H  —  —  J  (Dulong),  where  C,  H  and  O  mean  the  resp.  per  cent 

of  carbon,  hydrogen  and  oxygen. 

This  formula  requires  a  complete  elementary  analysis. 

An  easier  way  of  calculating  the  comparative  heating 
effect  of  different  solid  fuels  is  the  Berthiers  test.  In 
this  test  the  amount  of  lead  reduced  from  lead  oxide  by 
the  different  fuels  is  used  for  comparison. 

/.  Analyses  of  gases,  per  1OO  vol. 


CaH4 

C03 

o. 

CO. 

H. 

CH4 

N. 

Blast  furnace  gas  (charcoal  +  coke)  . 

— 

2®    5 

— 

io@35 

.i@    8 

O  @2 

55  ©65 

(coal)  

O©  1.6 

3  ©17 

— 

16  @  31 

•5®  12 

.1  @8 

50  ©66 

Producer  gas  (charcoal  +  coke)  

- 

5@    7 

— 

23  ©35 

i-S®    4 

0   @2 

63  ©65 

44          "    (coal) 

O  @  2 

A.  (eh   8 

O  (ob,    7 

2O  (^  21? 

o  e  (sh     g 

I    (^  2.  ^ 

60  @  68 

u          "    (wood  and  peat) 

O  ©  2 

4  Vjx>     o 
e  (ff\  TT 

\J  \!-^f     3 

O  @,    i 

T7  (?h    OT 

^•O  v4?      ° 

6  (9)  i* 

z  (5>  6 

51  @  59 

"         "    (water  gas)  

0  Vti*   ** 
I  (Si     7 

O  @  .8 

A/    (^   ^1 

oc  (fh  ACI 

u  \^f  15 

•  5  ^*  u 

3//7\    r 

Products  of  combustion  

1   VW#       / 
A    (fht    TC 

i  (db  16 

o5  V&  4U 
O  (Si     t 

44  ^S>  53 
O  (ob,    i 

^  5 

i  (^    9 

*7n  ^  RT 

Bessemer  converter  gas  

4   v£?    *•$ 

t  (oh  o 

O   vii>    ±u 

O  @    8 

W  m?    5 
O  @  2Q 

V  \ii*      3 
O  @.     2 

79  ^is?  OI 

Illuminating1  gas  

4  @  13 

.j.  vji?    y 
i  fib,    A. 

O  (cb>   7 

A  e  (7h    n 

e  ^1     e 

Products  of  distillation  of  pine  wood  . 

T.8 

.1  vjx^     4 

31.8 

V/  VJX^     ,7 

1.6 

4o  ^i?    y 
34-4 

21  (Q^  55 

7-1 

33~5° 
16.8 

•5  vti*    5 
6-5 

"        "           "          "peat  

1.4 

41-3 

*-3 

16.1 

19.6 

17.1 

3-2 

44          t4  can'l  coal.. 

13-6 

2.7 

1.9 

3-6 

JS-Q 

58-0 

6-3 

Natural   gas,    mostly    CH4,    with 
some  CO2  C2  H4,  O,  H,  N,  etc. 

Air  gas,  or  gas  obtained  by  blowing 
air  through  gasoline  

I 

1A 

tifi 

L*T 

27 

5° 

94 


NOTES  ON  THE  CHEMISTRY  OF  IRON. 


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CHAPTER   V. 

METALLURGICAL    NOTES    AND    PRACTICAL    USES   OF  THE  RE- 
SULTS   OF    ANALYSES. 

The  Chemical  Analysis  is  of  great  value  not  only 
technically,  but  also  commercially,  as  regards  pig- 
iron.  The  analysis  determines  to  a  great  extent  the 
suitability  of  ores,  fluxes,  etc.,  for  certain  kinds  of  pig- 
iron  and  other  alloys  of  iron  made  in  the  blast  furnace, 
and  it  determines  the  suitability  of  various  kinds  of  pig- 
iron  for  different  purposes,  such  as  castings,  Bessemer, 
Siemens-Martin,  Thomas,  crucible,  puddling  and  other 
processes. 

The  chemical  analysis  is  of  great  use  for  determin- 
ing, or  at  least  for  forming  an  idea  of,  the  refractory 
properties  of  sands,  clays,  etc. 

We  have  already  described  the  uses  of  gas  analysis 
for  various  purposes,  and  in  the  appendices  are  de- 
scribed several  practical  applications  of  gas  as  well 
as  other  analyses. 

For  wrought-iron  and  steel  the  chemical  analysis 
cannot  so  reliably  predict  the  physical  properties  as 
for  pig-iron.  This  has  already  been  pointed  out  in 
the  first  chapter  of  this  book.  But  it  may  do  so  in 
many  cases,  and  it  is  otherwise  exceedingly  useful  in 


96  NOTES   ON   THE   CHEMISTRY   OF   IRON. 

explaining  the  causes  and  tracing  the  sources  of  defects 
in  steel.  The  method  given  in  Chapter  II.  for  the  de- 
termination of  "  slag  and  oxide  of  iron  "  has  found  a 
special  application  for  distinguishing  wrought-iron  from 
steel  where  doubt  as  to  this  has  existed,  the  wrought- 
iron  containing  much  more  slag  and  oxide  of  iron  than 
the  steel. 

a.  Pig-iron.  The  suitability  of  an  ore  for  a  certain 
kind  of  pig  depends  upon  several  circumstances  besides 
the  chemical  composition,  such  as  physical  properties, 
supply  of  suitable  ores  of  other  kinds,  etc. 

In  selecting  ores  it  should  be  remembered  that  all 
the  phosphorus  goes  into  the  pig.  Only  with  a  very 
hot  furnace  and  a  basic  burden  can  any  phosphoric  acid 
be  brought  into  the  slag.  The  sulphur,  on  the  other 
hand,  can  be  removed  to  a  great  extent  under  similar 
circumstances,  passing  into  the  slag  as  Ca  S.  The  man- 
ganese has  a  very  great  tendency  to  pass  into  the  slag, 
its  affinity  for  oxygen  being  so  great,  that  ferromangan- 
ese  can  only  be  produced  at  temperatures  higher  than 
the  temperature  at  which  the  metal  manganese  is  vola- 
tilized. Spiegeleisen  and  ferromanganese  never  contain 
any  appreciable  amounts  of  sulphur,  the  sulphur  form- 
ing Mn  S  with  the  Mn  ;  the  Mn  S  is  not  soluble  in  the 
molten  alloy  and  passes  into  the  slag.  Silicon  is  readily 
reduced  by  carbon  at  high  temperatures  in  the  pres- 
ence of  metallic  iron.  The  pig-iron  becomes  more  car- 
boniferous the  more  manganese  and  the  less  silicon  and 
sulphur  it  contains  ;  even  phosphorus  acts  against  high 


METALLURGICAL  NOTES.  97 

carbon,  inasmuch  as  it  makes  the  metal  more  fusible, 
enabling  it  to  melt  without  taking  up  much  carbon. 
Rapid  driving  of  a  blast-furnace  counteracts  high  carbon. 

As  to  the  selection  of  ores,  the  proportion  between 
the  iron  and  the  phosphorus  in  the  ore  is  of  great  im- 
portance. Carbonates,  hydrates  and  ores  containing 
much  sulphur  are  generally  roasted  before  using ;  mag- 
netic iron-ores  are  also  generally  roasted  in  order  to 
convert  Fe3  O4  to  Fe2  O3,  which  is  easier  to  reduce.  In 
the  appendices  some  further  remarks  on  the  selection  of 
ores  will  be  found. 

The  amount  of  pig-iron  from  a  blast  furnace  obtained 
is  often  calculated  according  to  the  formula  : 


Pig  =  Fe  + 


2  20 


which  means  that  the  pig  contains  all  the  iron,  half  of 
the  manganese  and  metalloids  to  the  extent  of  5  per 
cent  of  the  metals.  For  very  phosphoriferous  pigs 
the  following  formula  comes  nearer  the  truth : 


For  castings  the  selection  of  suitable  pig-irons  is  of 
great  importance.  Gray  pig-iron  is  generally  used  for 
castings,  white  or  mixed  pig  being  used  chiefly  for 
chilled  and  malleable  castings.  The  user  of  cast-iron 


98  NOTES   ON   THE   CHEMISTRY   OF  IRON. 

must  know  the  physical  properties  of  the  material  as 
well  as  the  behavior  of  the  material  in  melting.  The 
latter  can  be  predicted  by  means  of  the  chemical  analy- 
sis of  the  pig.  The  manganese,  silicon  and  carbon  are 
more  or  less  oxidized  in  melting,  whilst  the  iron  in  the 
presence  of  those  easily  oxidized  elements  remains  in 
the  metallic  state.  The  relative  avidity  with  which  the 
three  elements  unite  with  oxygen  is  as  in  the  above 
order.  The  temperature  influences  the  oxidation  of 
carbon ;  at  very  high  temperatures  carbon  takes  up 
oxygen  even  at  the  expense  of  manganese  and  silicon. 
The  respective  amounts  of  the  elements  have  here,  as 
in  all  chemical  reactions,  much  to  do  with  the  result. 
The  phosphorus  remains  with  the  iron,  and  it  is  thus 
easily  understood  that  its  per  cent  should  become  some- 
what raised.  (Phosphorus  can  be  removed  from  pig- 
iron  according  to  a  process  devised  by  Bell  and  Knapp, 
by  melting  it  at  a  low  temperature  together  with  pure 
iron -ores.  The  pig  for  this  process  ought  to  contain 
some  manganese,  which  helps  to  protect  the  carbon 
and  silicon  from  oxidation  :)  The  manganese  protects 
the  silicon  during  melting  from  oxidation,  and  should 
therefore  always  be  present  to  some  extent  in  order  to 
prevent  the  pig  from  losing  its  gray  texture.  On  an 
average  the  manganese  in  good  pig-iron  for  castings 
does  not  exceed  i  per  cent,  the  silicon  2-3  per  cent, 
the  phosphorus  .5  per  cent,  the  graphite  and  combined 
carbon  together  about  4  per  cent.  The  respective 
amounts  of  graphite  and  combined  carbon  have  much 


METALLURGICAL  NOTES.  99 

influence  on  the  physical  properties  of  pig-iron.* 
Phosphorus  renders  the  pig  not  only  more  easily  fusi- 
ble but  also  more  fluid;  manganese  has  the  opposite 
effect. 

For  the  Bessemer  process  the  pig-iron  must  not  con- 
tain too  much  phosphorus,  as  the  later  is  not  removed 
in  the  "  acid  "  process.  The  Bessemer  process  is  carried 
out  rather  differently  in  different  countries  ;  one  gen- 
erally mentions  the  English,  the  German  and  the 
Swedish  process.  The  chief  characteristics  of  these 
three  processes  are  for  the  English  process,  a  not  very 
superheated  pig-iron,  rich  in  carbon  and  silicon  but  with 
little  manganese  ;  yields  a  metal  low  in  silicon.  For  the 
German  process,  a  superheated  pig-iron  with  much  man- 
ganese and  silicon  ;  yields  a  metal  with  low  carbon  but 
much  silicon  (vide  Chapter  I.  under  "  Influence  Phos- 
phorus.") For  the  Swedish  process,  a  hot  pig  from  the 
blast  furnace  with  much  manganese  and  carbon  ;  but 
not  a  very  high  per  cent  of  silicon,  and  remarkably  low 
in  phosphorus  ;  yields  a  metal  low  in  both  manganese 
and  silicon.  The  initial  temperature  of  the  pig  when 
charged  in  the  converter  has  very  much  to  do  with  the 
final  composition  of  the  product  (vide  above).  Finally, 
perhaps,  the  Clapp- Griffith's  process  should  be  men- 
tioned, as  a  modification  of  the  Bessemer  process.  In 
the  Clapp-Griffith  modification  a  soft  steel  is  principally 
made,  rich  in  phosphorus,  but  low  in  both  carbon  and 
silicon.  Very  few  analyses  have  been  published  of 

*  Dudley's  (Chas.  B.)  Transaction  Min.  Engineers. 


IOO  NOTES   ON   THE   CHEMISTRY   OF   IRON. 

metal  made  by  this  process,  but  it  seems  to  be  of  good 
quality,  although  this  is  probably  due  to  the  absence  of 
carbon,  silicon  acting  indifferently  toward  phosphorus, 
according  to  the  German  experience. 

To  demonstrate  the  influence  of  the  composition  of 
Bessemer  pig-iron  on  the  process,  some  data  are  here 
given  according  to  Professor  Ledebur,  Favre  and  Sil- 
bermann,  a.  o.  i  kg.  Fe  burnt  to  Fe  O  develops  1352 
h.  u.  giving  1.28  kg.  Fe  O  and  .94  kg.  nitrogen.  Spe- 
cific heat  of  Fe  O  =  .20,  of  N  =  .25.  Initial  tempera- 
ture of  the  iron  =  /.  Consequently  the  molten  iron 
possesses  an  initial  heat  of  .i8/  h.  u.,  if  .18  be  the  spe- 
cific heat  of  iron  between  fig.  o°  and  t°.  By  the  products 
of  combustion  are  taken  up  (1.28  x  .20  +  '94  x  .25)  t 
h.  u.,  and  the  total  number  of  the  heat  units  that 
benefits  the  iron-bath  is  therefore  =  1352  +  .  i8/  — 
.49 \t  =  1353  —  .311^  for  every  kg.  of  iron  burnt  to 
Fe  O.  If  t  be  =  1500°  we  thus  find  W  =  886  h.  u., 
and  if  we  put  the  specific  heat  of  iron  at  1500°  =  .20 
we  find  the  increase  of  temperature  caused  by  the  com- 

8.86 
bustion  of  i  per  cent  of  iron  =   :  =  44  per  cent  only. 

i  kg.  Mn  to  1.29  kg.  Mn  O  4-     .97  kg.  N  develops  about  2000  h.  u. 

"    C     "  2.33    "   CO  4-  4-47      "         <l  "       2473     " 

"     Si     "  2.14   "   Si02  4-  3.82      "          "  "       7830     " 

"     P      "2.29   "   P2O5  4-4.00      "          "  "       5760     " 

Specific  heat  of  Mn  =  .18,  of  MnO  =  .20 

'<         "       "  C     =  .25    "  CO  =  .25 

"         "       "  Si    =  .18   "  Si  O2  =  .19 

"      "  P     =  .18   "  P2  05  =  .25 


METALLURGICAL  NOTES.  IOI 

By  similar  calculations  as  those  for  iron  we  find, 

for  Mn,  W  =  2000  —    .42^. 

"   C,      W=  2473  -  1-45'. 

"    Si,      W  =  7830  -  i.i8/. 

"    P,      ^-576o  -  i.39/. 

or  if  /  =    1500°,   for  the  combustion  of  i   per  cent  of 

either  of  the  above  elements,  a  raise  of  temperature, 

for  Mn,  of     69°  C. 

"   C,      "       6°  C. 

"   Si,      "   300°  C. 

"   P,      "    183°  C. 

It  is  evident,  from  the  above  figures,  that  the  carbon 
cannot  furnish  enough  heat  to  carry  through  the  Besse- 
mer process,  silicon  and,  in  the  basic  process,  silicon  and 
phosphorus  being  the  principal  heaters.  The  facility 
with  which  good  soft  steel  is  made  by  the  basic  process 
depends  largely  upon  the  heating  properties  of  phos- 
phorus, which  burns  in  the  last  stage  of  the  process 
when  the  metal  has  become  more  refractory  and  needs 
much  heat.  Pig-iron  for  the  basic  process  contains 
generally  from  2  —  3  per  cent  of  P,  .5  to  2  per  cent  of 
Mn  and  1.19  —  .5  per  cent  of  Si. 

Pig-iron  for  the  Siemens-Martin  process  may  be 
either  gray  or  white,  but  should  have  much  carbon. 
The  most  suitable  pig-iron  for  the  open-hearth  process  is 
generally  a  pig  containing  little  P  and  S,  but  2—5.5  Per 
cent  Si,  3  —  3.5  per  cent  Mn  and  3.5  —  4  per  cent  C. 

Pig-iron  for  the  carbonization  in  crucibles  should  con- 
tain nearly  only  carbon  and  iron ;  such  pig  is  obtaina- 
ble from  some  famous  furnaces  in  Sweden. 


102  NOTES   ON  THE   CHEMISTRY   OF  IRON. 

b.  Steel.  It  has  already  been  mentioned  that  chem- 
ical analysis  alone  cannot  predict  the  suitability  of  a 
steel  for  different  purposes. 

But  the  analysis  has  done  much  to  remove  existing 
mystery  and  prejudice  concerning  the  crucible  and 
other  processes. 

A  characteristic  property  of  crucible  steel  is  its  large 
percentage  of  silicon,  which  varies  between  .3  and  .5 
per  cent,  and  seldom  goes  down  to  .  i  per  cent.  The 
manganese  is  seldom  over. 3  per  cent ;  the  carbon  varies 
according  to  the  different  purposes  for  which  it  is  in- 
tended. The  high  silicon  is  by  no  means  beneficial  to 
the  quality  of  crucible  steel,  and  crucibles  containing 
more  alumina  and  less  silica  would  seem  to  be  the  rem- 
edy for  this  evil.  It  is  claimed  for  the  crucible  steel  that 
it  contains  less  gases  than  steel  made  by  other  processes. 

The  Bessemer  product  varies  in  composition  accord- 
ing to  the  different  purposes  for  which  it  is  intended, 
and  also  according  to  local  circumstances.  A  few  ex- 
amples are  here  given  : 


Hard  steel  from  Gras,  Austria 

Tool  steel  "  Fagersta,  Sweden 

"  "  "  Midvale,  U.  S.  A. 

Axle  "  "  Leraing,  Belgium 

Rail  "  "  Osnabruck,  Germany 

"  "  "  Bethlehem,  Pa. 

Steel  for  plates  "  Fagersta 

Thomas  steel  "  Vitkowitz,  Austria 
Soft  steel  for  nails,  Hofors,  Sweden 


C  Si  Mn  P 

1.03  .02  .25  .09 

.70  .03  .26  .025 

i.oo  .10  .27  .027 

.49  .09  .60  .07 

.19  .50  .87  .14 

•35  -05  -75  -°8 

.09  .01  tr  .025 

.10  tr  .20  tr 

,10— .15  .02  .14  .027 


METALLURGICAL  NOTES.  1 03 

The  Siemens-Martin  metal  also  varies  according  to 
purpose. 

The  so  called  "  Mitis"  process,  which  has  lately  come 
into  use,  gives  very  good  castings  of  the  softest  iron 
steel.  According  to  information  received,  the  castings 
are  obtained  solid  by  heating  the  soft  scrap  used  as  raw 
material  to  the  point  when  it  just  melts,  and  then  add- 
ing an  aluminium  alloy,  which  lowers  the  melting  point 
and  causes  the  metal  to  become  super-heated.  The 
melted  scrap  does  not  take  up  any  gases,  being  heated 
only  to  the  melting  point  before  adding  the  aluminium. 
Aluminium  has  thus  become  of  interest  in  the  chemistry 
of  iron,  and  it  can  readily  be  determined  in  steel  by  a 
method  similar  in  part  to  the  one  given  in  Chapter  II. 
for  titanium.*  It  may  also  be  determined  by  difference 
after  estimating  the  amounts  of  other  ingredients. 

As  to  the  influence  of  the  various  elements  on  the 
properties  of  steel,  this  has  already  been  alluded  to  in 
the  first  chapter.  We  may  add  that  the  effect  of  man- 
ganese is  about  ^  that  of  carbon.  Manganese  seems  to 
increase  the  facility  of  iron  to  absorb  and  dissolve  gases. 
Phosphorus,  silicon  and  carbon  protect  iron  and  steel 
against  rust,  whilst  manganese  and  sulphur  promote 
rust.  Steel  has  more  tendency  to  become  rusty  than 
wrought-iron,  which  is  probably  due  to  the  larger 
amounts  of  manganese  and  sulphur  in  the  former. 

The    changes    of  steel  when  heated   and  cooled  are 

*  It  should  be  borne  in  mind  that  an  equal  amount  of  iron  must  be  present  to 
effect  a  rapid  and  complete  precipitation  of  the  aluminium  by  basic  acetate. 


IO4  NOTES   ON  THE   CHEMISTRY  OF  IRON. 

many  and  important.  Mr.  Brinell,  of  Fagersta,  has 
made  experiments*  on  the  changes  of  texture,  and  has 
come  to  the  following  conclusions  : 

i  st.  When  steel  loses  its  coarse  crystalline  texture 
without  mechanical  treatment,  this  is  always  accompa- 
nied by  the  transformation  of  carbon  from  cement  to 
hardeningf  carbon  or  vice  versa.  The  change  of  tex- 
ture is  exclusively  due  to  the  change  of  state  of 
carbon. 

2d.  The  coarse  crystalline  texture  disappears  com- 
pletely only  when  the  carbon  during  heating  changes 
from  cement  to  hardening  carbon.  In  accordance  with 
this  the  most  coarsely  cyrstalline,  hardened  or  unhard- 
ened,  steel  loses  this  texture  completely  if  heated  just 
to  the  point  where  the  cement  carbon  changes  to  hard- 
ening carbon. 

3d.  In  order  to  convert  the  carbon  into  cement  car- 
bon in  white-hot  steel,  it  must  be  cooled  to  a  point 
lower  than  the  point  to  which  unhardened  steel  must  be 
heated  in  order  to  have  the  carbon  converted  into  hard- 
ening carbon. 

4th.  The  change  to  hardening  carbon  takes  place 
rapidly  at  the  proper  heat. 

The  change  to  cement  carbon  takes  place  slowly  either 
during  the  heating  up  or  during  the  cooling. 


*  The  steel  for  trial  had  C  =  .52,  Si  =  .13,  P  =  .026,  Mn  =  .48. 

|  Steel  containing  only  hardening  carbon,  when  treated  with  dilute  nitric  acid, 
gives  a  sootlike  carbon,  brown  on  paper  ;  cement  carbon  a  bluish  glistening  car- 
bon, black  on  paper. 


METALLURGICAL  NOTES.  1 05 

5th.  Heat  is  always  set  free  when  hardening  carbon 
changes  into  cement  carbon,  and  probably,  therefore, 
heat  is  absorbed  when  the  opposite  reaction  takes  place. 

6th.  When  the  hardening  carbon,  either  during  cool- 
ing or  heating,  has  been  completely  changed  into  cement 
carbon  the  texture  suddenly  becomes  coarsely  crystal- 
line, and  more  so,  the  more  coarsely  crystalline  it  was 
before. 

7th.  Rapid  cooling  can  never  produce  a  fine  texture  in 
a  previously  coarsely  crystalline  steel.  It  only  fixes  the 
texture  existing  before  the  cooling. 

8th.  The  change  from  hardening  to  cement  carbon 
requires  a  suitable  heat  and  time,  whilst  the  reverse  re- 
action seems  to  depend  exclusively  upon  the  degree  of 
heat.  This  is  the  reason  why  a  rapid  cooling  prevents 
hardening  carbon  from  changing  into  cement  carbon. 

9th.  For  the  crystallization  of  steel  time  is  required. 
If  the  steel  be  rapidly  cooled  the  development  of  crys- 
tals is  thus  checked. 

At  a  <4  blue  heat "  all  kinds  of  steel  seem  to  be  very 
coarsely  crystalline  and  brittle.  Mr.  Brinell's  experi- 
ments confirm  this.  When  steel  is  gradually  heated  its 
color  changes  about  as  follows  with  the  temperature  : 

Yellow,     .     .     .      220°  C.     purple  red,     .     .     .  275° 

Dark  yellow,      .      240°  "      violet,       .     .     .     ;  285° 

Brown  yellow,    .      250°  "      bluish,       ....  293° 

"     red,     .     .      265°  "      light  blue,     .     .     .  315° 

gray, 33°° 

To  illustrate  the  changes  of  strength  of  steel  with  the 


IO6  NOTES   ON  THE   CHEMISTRY   OF  IRON. 

carbon,  the  other  composition  being  the  same,  the  fol- 
lowing figures  are  given  : 

Lbs.  p.  sq.  in. 

Carbon  =  .55,  tensile  strength  106,000,  elong.  per  cent.  32  per  cent. 
"      =  -65,  "  117,000,    «  "  24       " 

"      =  .75,  "  126,000,   "  "  19       « 

"      =  .85,  «  140,000,   «  "  13 

"      =  -95,  "  140,000,   "  «  13 

c.  Notes  on  refractory  materials.  Silica,  Alumina, 
lime  and  magnesia,  iron  peroxide  and  tetroxide  and 
clay,  as  well  as  graphite,  are  the  principal  refractory 
materials  used  in  iron-steel  making.  The  clays  are  very 
variable  in  chemical  composition.  They  consist  of 
aluminium  hydrate  and  silicate,  with  varying  amounts 
of  alkalis,  lime,  magnesia,  iron  hydrates,  etc.  When 
the  sum  of  the  latter  ingredients  amounts  to  more  than 
ten  per  cent.,  the  clay  cannot  longer  be  considered  re- 
fractory. The  silica  occurs  not  only  in  combination 
with  alumina,  but  also  in  the  free  state.  As  an  illustra* 
tion  two  extremes  are  here  given  : 

Clay  i.  Clay  2. 

Al,  O3  .     .    ;   V  V    .     36-30 28-°5 

Comb.  Si  O2 .     .     .     .     38.94     ......  30.71 

Free  Si  O2     ....        4.90 27.61 

Foreign  ingred.       .     .        1.26 4-75 

Loss  on  ignition      .     .      17.78 8.66 


CHAPTER  VI. 

Notes  on  Electrolysis.*  The  electrolysis  is  beginning 
to  find  application  not  only  to  fluids  but  also  to  melted 
minerals. 

The  most  striking  advantage  of  electrolysis  is  the 
pure  state  in  which  metals  can  be  separated  by  means 
of  the  same.  It  is  beyond  the  province  of  this  book  to 
discuss  the  practical  applications  of  electrolysis,  and  only 
some  important  principles  upon  which  its  application  is 
based  can  be  communicated. 

Berthelot  has  given  the  following  laws  :  ist.  The  heat 
developed  in  a  chemical  reaction  is  a  measure  of  the 
physical  or  chemical  work  performed — molecular  work. 

2d.  If  a  given  combination  of  simple  or  compound 
bodies  undergoes  a  change  without  external  mechanical 
force  the  heat  developed  or  absorbed  depends  only  upon 
the  initial  and  final  conditions  of  the  combination,  of 
whatever  kind  the  intermediate  changes  may  have  been 
— equivalence  between  heat  and  chemical  change. 

3d.  Every  chemical  change  which  takes  place  spon- 
taneously results  in  the  production  of  such  compounds 
in  the  formation  of  which  the  most  heat  is  developed. 

Heat  is  developed  when  elements  combine  chemically, 
and  if  this  heat  be  known,  the  amount  of  force  necessary 

*  Balling. 


io8 


NOTES   ON   THE   CHEMISTRY   OF   IRON. 


for  decomposition  can  be  calculated.  Favre  and  Silber- 
mann  found  the  following  number  of  heat  units  in  the 
formation  of  the  compounds  enumerated  : 

For  i  part  of  iron  to  Fe  O 

Fe2Cl6 
"         "         «  FeCl2 

FeS 
"         "     Zinc  ZnO 

ZnCl2 
"     Copper  CuO 

CuCl2 

"         "         "  OS 

"     Lead  PbO 

"       "  PbCl2 

"         "       "  Pb  S 

"         "     Tin  SnO2 

"       "  SnCl* 

"         "     Silver  Ag;  O 

"         "         "  AgCl 

Ag2  S 

According  to  Thompson,  the  equivalent  numbers  of 
heat  units  corresponding  to  the  formation  or  decompo- 
sition of  various  compounds  is  as  follows,  in  aqueous 
solutions  : 

AU  C13          27270 

MnCl2        128000 

Zn  C12         121250 

Zn  SO*        106090 

FeCl2  99950 

Fe2Cl6 

Fe  SO4 

Fe,  3SO, 


FOR  i  EQUI 

1353 

75656 

1745 

196170 

1775 

99302 

634 

35506 

1291 

83915 

I529 

101316 

684 

43770 

961 

60988 

285 

18266 

266 

55350 

430 

89460 

92 

I9II2 

1147 

^5360 

1079 

126888 

57 

12226 

322 

34800 

51 

II048 

93200 
224800 


Ag2  SO* 

20390 

AgN03 

16780 

CuSO4 

55960 

CuCl2 

62710 

Cu  2N03 

52410 

Pb2NO3 

69970 

Pb  2C2  H3  O 

65760 

NOTES   ON   ELECTROLYSIS. 


IO9 


The  metals  develop,  according  to  Thompson,  the  fol- 
lowing numbers  of  heat  units  when  entering  into  the 
following  solid  compounds  : 


Cu  to  Cu2  O 

40810.2 

Cu2  S  : 

18069. 

Cud 

65750 

"       CuO 

37160. 

CuCl2 

5i630 

Fe       Fe  O 

99232. 

Fe  S    : 

35504. 

FeCl2 

82050 

« 

— 

Fe2  C16 

196170 

Zn        Zn  O 

85430- 

Zn  S    : 

41989. 

ZnCl2 

97210 

Pb        Pb  O 

50300. 

Pb  S    : 

19044. 

Pb  Cl,> 

82770 

Ag       Ag2  0 

5900. 

AgCl 

29380 

Hg       Hg,  0 

42200. 

HgCl 

82550 

"        HgO 

30660. 

HgCl2 

63160 

An          — 

— 

An  Cl, 

22820 

In  a  Daniell's  cell  zinc  is  dissolved  and  copper  pre- 
cipitated ;  thus  we  have  : 

106090  —  55960  =  50130  h.  u. 

All  this  heat  cannot  be  converted  into  electricity ; 
according  to  Kiliani  only  83  per  cent  in  the  case  of 
Zn  SO4  and  68  per  cent  in  the  case  of  Cu  SO4.  The 
50,130  h.  u.  are  a  measure  of  the  electromotive  power 
of  the  cell,  and  by  dividing  the  numbers  of  heat  units 
developed  according  to  Thompson  in  the  formation  of 
the  compounds  enumerated  above  we  find  how  many 
volts  are  required  to  decompose  any  of  said  compounds. 

One  Daniell  cell  is  =  1.12  volt,  the  "  volt  "  being  the 
unit  of  electromotive  power. 


.          i  volt 

i  ampere  =  — ; — 

i  ohm 


HO  NOTES  ON  THE   CHEMISTRY   OF  IRON. 

=  strength  of  current ;  the  ampere  —  current  precipi- 
tates in  one  minute  19.85  mg  Cu  and  67.57  mg  Ag. 

The  Ohm  is  the  unit  of  resistance,  not  quite  accu- 
rately determined.  The  ohm  is  about  =  95  per  cent 
of  a  Siemens  unit,  or  the  resistance  of  a  column  of 
mercury  i  m.  long  and  i  sq.  m.  m.  thick.  The  resist- 

length  of  conductor 

ance  is  —   -. — ^—    ^—  —   x    the  sp.  resist- 

sectional  area  ot  conductor 

ance  of  the  substance  in  question.  The  sp.  res.  of 
various  elements  are  as  follows,  according  to  Matthies- 
sen  : 

Cu            %          i.oo  Pt  7.35 

Ag  .77  Pb  9.96 

Au  1.38  SC  18.07 

Al  2.29  Hg  47-48 

Zn  2.82  Bi  64.52 

Fe  5.36  Graphite  1 106.00 

Sn  6.76  Gas-coke  2037.00 

For  actual  metallurgical  purposes  galvanic  elements 
are  not  sufficiently  strong,  and  dynamo-electric  machines 
have  to  be  used  in  such  cases. 

i  weight  of  coal  gives  about  7500  h.  u.,  but  of  these 
only  about  360  can  be  converted  into  electricity  in  the 
dynamo-electric  machine. 

The  working  effect  of  a  current  per  second  is  ex- 
pressed by  the  product  of  the  electromotive  force  in 
volts  and  the  strength  of  current  in  amperes.  One 
horse-power  is  =  75  meter-kilog.  per  second,  and  ac- 
celeration by  gravitation  is  9.81  m.  If  V  =  el.  mot. 
power  and  A  =  strength  of  current,  we  have 


NOTES   ON   ELECTROLYSIS.  I  I  I 

A  X  V 

— •  —  electrical  effect  of  a  current  in  meter-kilog., 

and 

A  x  V 

—5 =  the  effect  in  horse-power. 

9.81   x  75 

(For  more  complete  information  on  electrical  matters, 
the  reader  is  referred  to  "Electricity  and  Electrical 
Engineering,"  by  Fiske  (Nostrand,  New  York). 

The  electrical  units  are  briefly  as  follows  : 

i  dyne  —  — -  of  a  gram. 
901 

i  erg     =  i  dyne  —  centimetre. 

i  electrostatic  unit  of  electricity  is  such  a  quantity  as 
acts  with  one  dyne  on  a  similar  quantity  at  a  distance 
of  one  centimetre. 

Current  of  unit  strength  is  such  a  current  as  will  act 
with  the  force  of  one  dyne  upon  a  magnet  pole  placed 
at  the  centre  of  a  circle  indicated  by  the  conductor  i 
centimetre  long  bent  into  an  arc  with  i  centimetre 
radius. 

The  unit  quantity  of  current  electricity  is  the  quan- 
tity carried  in  one  second  by  a  current  of  unit  strength 
(C.  G.  S.  unit,  centimetre,  gram,  second),  electromag- 
netic unit  of  electricity. 

The  electromagnetic  unit  is  much  larger  than  the 
electrostatic  unit,  but  as  in  both  cases  it  should  require 
i  erg  of  work  to  give  to  each  a  unit  of  "  potential,"  or 
electromotive  force,  it  follows  that  the  electromag- 


112  NOTES   ON  THE   CHEMISTRY   OF  IRON. 

netic  unit  of  electromotive  force  is  much  smaller  than 
the  electrostatic. 

The  following  are  the  practical  electromagnetic  units, 
which  are  derived  from  the  above  C.  G.  S.  units. 

Electromotive  force  unit  (difference  of  potential,  potential)  =  Volt 
io8  (C.  G.  S.)  unit. 

Resistance  unit  =  ohm   =  io9  (C.  G.  S.)  unit. 

Strength  of  current  unit  =  ampere    =  io  — *  (C.  G.  S.)  unit. 

Quantity  of  current  unit  =  coulomb  =  io  — T  (C.  G.  S.)  unit. 

Unit  of  electrical  work   =  volt  x  coulomb  =  joule. 

Unit  of  electrical  power  =  volt  x  ampere  =  watt. 

i  joule  —  .1020  kilogram  metres. 

i  watt  —  — 2  horse-power  =  —j-  =  .102  kilogram  metres  per  se- 
cond. 


APPENDICES. 


APPENDICES. 


UNIVERSITY 


A. 

HEAT   CALCULATIONS. 

(Heat  unit  =  heat  required  to  raise  the  temperature  of  i  kilo,  water  i°  C.) 

TABLE  I.  —  Gases  at  o°  and  760  Millimetres,  according  to  Bunsen. 


Sp.  gr.  referred 
to  hydrogen. 

Sp.  gr.  ref. 
to  air. 

Weight  of 
1,000  liters 
—  i  cubic 
metre  kilo. 

SPECIFIC  HEAT. 

HEAT  UNITS  DEVEL- 
OPED BY 

Per  i  kilo. 

Per  i  c.  m. 

Per  i  kilo. 

Per  i  c.  m. 

Air, 

[|8j  ,4.435] 

1.  000 

1.2936 

.2370 

.3066 

— 

— 

Oxygen, 

O=i6.o 

1.1056 

I4303 

.2182 

.3120 

— 

— 

Nitrogen, 

N=i4.o 

.9713 

1.2566 

.2440 

.3066 

— 

— 

Hydrogen, 

H—  i.o 

.0692 

.0896 

3.4046 

•3051 

(  34462 

i  29633* 

3088 
2655* 

Carb.  acid, 

CO2 

—  =22.0 

1.5202 

1.9666 

.2164 

•4256 

Carb.  oxide, 

CO 

~T—  M.O 

.9674 

i.25'5 

•2479 

•3I03 

2403 

3007  1 

Carbon  gas, 

C=I2.0 

.8292 

1.0727 

— 

— 

— 

— 

Marsh  gas, 

CH4_ 

—  -  8.0 

•5531 

.7155 

•5929 

.4242 

11856* 

8482* 

Ethylene, 

C2H4 

.9678 

1.2520 

.3694 

.4625 

11162* 

13982* 

2 

Sulph.  acid, 

S02 

—  =32.0 

2.2139 

2.8640 

.1553 

— 

— 

— 

H2S 

Sulphur,  hy., 

2 

1.1776 

1.5234 

.2423 

— 

2457 

3743 

Hydro,  acid, 

H  Cl 

1.2597 

1.6296 

.1845 

•387 

— 

— 

2      ~l8-2 

H2O 

Steam, 

-r-=  9-0 

.6221 

.8048 

•475 

•3823 

*  The  H  burnt  to  H2O,  which  passes  off  at  100°. 

t  i  kilo,  of        C       burnt  to  CO2  gives  8080  heat  unit. 

«    «     «        «          «      "CO      "      2473     "      " 

.5363    "     «        "  "       "C02     "      4334    "      " 

"       "     "        "          "      "CO     "     1327    "      «• 

j    "     "sulphur     "      "SO8     "     2221    "      " 


APPENDICES. 


TABLE  II.  —  Number  of  Heat  Units  developed  by  Different  Volumes  of 
the  Combustible  Gases.     (  Vide  TABLE  I.) 


Volumes  of 
gas,  c.  m. 

Hydrogen,  Heat 
Units. 

Carbonic  Oxide,  Heat 

Units. 

Marsh  Gas,  Heat 

Units. 

Ethylene,  Heat 
Units. 

I 

2655 

3007 

8482 

13982 

2 

5310 

6014 

16964 

27964 

3 

7965 

9O2I 

25446 

41946 

4 

10620 

12028 

33928 

55928 

5 

13275 

!5°35 

42410 

69910 

6 

15930 

18042 

50892 

83892 

7 

T8S85 

21049 

59374 

97874 

8 

21240 

24056 

67856 

111856 

9 

23895 

27063 

76338 

125838 

EXAMPLE : 


A  nalysis : 
CO2    =     4.0  vol. 

O        =     i.o  " 

C2H4=     i.o  " 

CO        =    22.0  " 

H       =     5.0  " 

CH4  =     i.o  " 

N        =  66.0  " 


Calorific  effect : 
i  c.  m.  CjH4  gives 


CO 
CO 

H 

CH4 


60140  heat  units 
6014    "      " 


13982  heat  units. 


66154 
13275 
8482 


Total, 


101893     '  per  100  c.  m.,  or  1018.93 

heat  units  per  i  c.  m. 


APPENDICES. 


117 


TABLE  III. — Number  of  Heat  Units  carried  off  by  the  Products  of 
Combustion  ;  the  Gases  being  burnt  with  the  Minimum  Amount  of 
Air,  containing  by  Volume  I  Oxygen  to  4  Nitrogen.  The  Flame 
Temperature,  or  Theoretical  Temperature,  for  a  Certain  Gas  is 
obtained  by  dividing  the  Calorific  Power  deducted  from  TABLE  II.  by 
the  Number  obtained  from  TABLE  HI.  for  the  same  Gas. 


'rt 

0 

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(jg       Xcg^ 

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C/D-C        $j 

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1.039 

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3-645 

5.298 

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2.078 

1.992 

7.290 

10.596 

.614 

3 

1.275 

3-ir7 

2.988 

1  °-935 

15.894 

.921 

4 

1.700 

4.156 

3-984 

14.580 

21.192 

1.228 

5 

2.125 

5-195 

4.980 

18.225 

26.490 

i-535 

6 

2-55° 

6.234 

5-976 

21.870 

31-788 

1.842 

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2.975 

7-273 

6.972 

25-5I5 

37.086 

2.149 

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3.400 

8.312 

7.968 

29.160 

42.384 

2.456 

9 

3-825 

9.35. 

8.964 

32.805 

47.682 

2-763 

The  figures  given  in  this  table  give  the  heat  units  carried  off  for  each  degree  of  temperature. 
EXAMPLE.     [Compare  Analysis  and  Calculation,  p.  88.] 

1.700 


4  vol.  of  CO2  carry  off  heat  units     . 
20  vol  of  CO  cause  the  carrying  off  of 


CO 


20.78 
2.07 


H 
CH4" 


'    N  —  4  (to  correct  for  i  vol.  ox.  present  in  the  gas)  62  vol. 
Total  heat  units  carried  off  per  100  c.  m.  of  gas  .        .        . 

Flame  temperature  =  -—  —  =  1772°  C. 


22.85 
4.98 
3.64 
5.29 

19.03 

57-490 


118 


APPENDICES. 


TABLE  IV. — Number  of  Heat  Units  carried  off  by  the  Products  of 
Combustion  for  each  degree  of  temperature,  the  Gases  being  burnt 
with  pure  Oxygen;  the  theoretical  temperature  obtained  as  before. 


. 

i 

I 

ol 

rt          . 

O     x. 

1 

>  in  Cubic  Metres. 

ied  off  by  the  COa 
ias: 
:O2  x  .425. 

ied  off  by  the  CO2  : 
he  CO: 
CO  x  .425. 

i 
JJjf 

*  u       x 

>vf3     ^ 

•°      ?? 
IB  - 

U     E 

43^ 

A 

il?4 

ed  off  by  the  Nitrog 
it  in  the  Gas  : 
N  x  .307. 

• 
O 

SsH 

§6-3 

b'O'T? 
o  ^v2 

sS  *„. 

rt|  x' 

ill 

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H* 

*£> 

la 

.•§    5 

«(/)£ 

w  O. 

C'S 

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s-S 

C  JJ3 

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fife 

S-2 
S§ 

|l 

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|l 

j|J* 

Sll 

u 

> 

K 

* 

s    « 

ffirt 

I 

.425 

•  425 

.382 

1.189 

1.414 

.307 

2 

.850 

.850 

.764 

2    378 

2.828 

.614 

3 

1.275 

1-275 

1.146 

3-567 

4.242 

.921 

4 

1.700 

1.700 

1.528 

4.756 

5.656 

1.228 

5 

2.125 

2.125 

1.910 

5-945 

7.070 

1.535 

6 

2.550 

2    550 

2.292 

7-134 

8.484 

1.842 

7 

2-975 

2-975 

2.674 

8.323 

9.898 

2.149 

8 

3-400 

3.400 

3-056 

9.512 

11.312 

2.456 

9 

3-825 

3.825 

3-438 

10.701 

12.726 

2.763 

Per  kilog.  oxygen  J  combinin&  with  or  j.  Fe  to  FeO  J  is  **£%£  I  473^  heat  units. 
j    separating  from    f  j  or  absorbed  f  */J 

"       "           "                    "             "            "  44  Fe304           "  4326 

"       44           »                    »             «            44   «  Fe203           "  4190 

"       "           "                    44             "          Mn  "  MnO            "  6875 

«4  u   MnO2           "  4110 

Iron  burnt  to  or  reduced  from  Fe2O3  develops  or  absorbs  1796 

"     Fe304          "  "  "        1648 

Manganese      i4        "            u           *4     MnO2          '4  "  '4        2410 

EXAMPLE.      [Compare  Analysis  and  Calculation,  p.  <&£] 


4  vol.  of  CO2  carry  off  heat  units 


"  CO  cause  the  carrying  off  of 8.5 

ii  co     u        4i         u          u    .i   <  >8 


H 


"  C2H4  "        "         «« 

"  N — 4  (to  correct  for  i  vol.  ox.  present  in  the  gas) 

Total  heat  units  carried  off  for  each  degree  of  temperature 

Flame  temperature  =  IQI  93 
34-543 


1.700 


9.30° 
1.910 
1.189 
1.414 
19.030 


34-543 


APPENDICES. 


TABLE  V. — Number  of  Heat  Units  developed  by  Different  Weights  of 
the  Combustible  Gases.     (Vide  TABLE  I.) 


Weights  of 
gas,  kilog. 

Hydrogen,  Heat 
Units. 

Carbonic  Oxide, 
Heat  Units. 

Marsh  Gas,  Heat 
Units. 

Ethylene,  Heat 
Units. 

I 

29633 

2403 

11856 

Ill62 

2 

59266 

4806 

23712 

22324 

3 

88899 

7209 

35568 

33486 

4 

118532 

9612 

47424 

44648 

5 

148165 

I20I5 

59280 

55810 

6 

177798 

14418 

7"36 

66972 

7 

207431 

I682I 

82992 

78134 

8 

237064 

19224 

94848 

89296 

9 

266697 

21627 

106704 

100458 

EXAMPLE.     [Analysis,  page 


CO3   =  vol.   4.0  ' 

O            =       "         1.0 

C,H4  =    "     i.o 

CO        =       "      22.0 

H       =    "     5.0 

CsFl4     —                 I.O 

N        =     "    66.0 

To  convert  to 
%  by  weight,  mul- 
tiply the  respect- 
ive volumes  with 
their    respective 
specific     gravity 
referred    to    hy- 
drogen, vide 
Table  I. 

'    4  x  22  =    88  =    6.4#  weij 
i  x  16  =    16  =    \.i% 
i  x  14  =    14  =    i.o}< 

22    X    14  =   308  =  22.6$ 

Sxi=      5  =      .3fc 
1x8=      8=      .& 
66  x  14  =  924  =  68  .  \% 

jhtc 

fCOa. 
0. 
C2H4. 
CO. 
H. 
CH4. 
N. 

IOO.O 

1363     100.0$ 

Thus  we  find  that  100  kilog.  gas  develop  78845  heat  units.  By  a  similar  calculation  to  that 
on  page  89,  we  find  the  flame  temperature  (correcting  the  nitrogen  for  the  oxygen  present  by 
subtracting  i.i  x  3.3),  which  should  agree  with  the  temperature  found  the  other  way. 


120 


APPENDICES. 


TABLE  VI.— Number  of  Heat  Units  carried  off  by  the  Products  of 
Combustion  for  each  degree  of  temperature  ;  the  Gases  being  burnt 
with  the  Minimum  Amount  of  Air,  containing  23.2  %  of  Oxygen 
and  76.8$  of  Nitrogen.  Theoretical  temperature  obtained  as  before. 


CARBONIC 
ACID. 

CARBONIC 
OXIDE. 

HYDROGEN. 

MARSH  GAS. 

ETHYLENE. 

NITROGEN. 

lj 

x 

s!° 

x'| 

ffit. 

Jx^xxx 

•4- 

8 

fa 

box  N 

jf+S-*? 

'£  5  w  ^^j 

x 

§ 
» 

|5.f; 

Is- 

x+E 

•pxfSs 

^r?n 

f 

.216 

•797 

10.446 

3.882 

4.027 

.244 

.432 

1.594 

20.892 

7.764 

8.054 

.488 

.648 

2.391 

3L338 

11.646 

12.081 

•732 

.864 

3.188 

41  .  784 

15.528 

16.108 

.976 

1.080 

3-985 

52.230 

19.410 

20.135 

1.220 

1.296 

4.782 

62.676 

23.292 

24.162 

1.464 

1.512 

5.579 

73-122 

27.174 

28.189 

1.708 

1.728 

6.376 

83.568 

31.066 

32.216 

1.952 

1-944 

7-173 

94  014 

34.948 

36.243 

2.196 

APPENDICES. 


B. 


CALCULATION  OF  BLAST-FURNACE  BURDEN  FROM  THE 
ANALYSES  OF  ORES,  FLUXES,  AND  FUEL-ASH,  BY  MEANS 
OF  MRAZEK'S  TABLE. 

THE  fluxing  table,  given  on  p.  92,  is  very  simple  and  easily 
understood  from  a  direct  study  of  the  same.  The  table  shows 
at  a  glance  the  amounts  required  of  each  substance  to  give  a 
slag  of  a  certain  composition.  The  equivalents  in  the  last  col- 
umns give  the  amounts  of  ore,  etc.,  required  to  give  one  part 
of  oxygen  in  excess  of  the  respective  proportions  between  the 
oxygen  in  the  bases  and  the  oxygen  in  the  silica.  Thus  when 
the  desired  basicity  or  acidity  has  been  obtained  it  is  easy 
to  find  from  the  other  columns  the  proportion  between  the 
alumina  and  the  other  bases,  the  proportion  between  lime  and 
magnesia,  the  proportion  between  iron  and  slag,  etc.  If  man- 
ganese is  present,  it  is  supposed  that  about  one-half  of  the 
same  goes  into  the  slag,  the  other  half  being  added  to  the 
iron.  There  is  no  need,  in  this  calculation,  of  taking  notice 
of  other  elements  that  are  reduced  and  added  to  the  iron  in  the 
blast-furnace. 

Alumina  makes  a  refractory  slag,  and  promotes  the  forma- 
tion of  gray  pig-iron  ;  so  does  magnesia.  Mzich  slag  also 
promotes  the  formation  of  gray  pig-iron.  In  general,  the  pro- 
portion of  alumina  to  the  other  bases  ought  not  to  exceed  one 
to  three.  The  relation  of  magnesia  to  lime  should  not  be 
much  above  one  to  two.  The  relation  of  slag  to  iron  varies 
between  six  tenths  to  one,  and  two  to  one. 

When  calculating  the  blast-furnace  burden  from  careful 
chemical  analyses,  it  should  be  borne  in  mind  that  the  physi- 
cal properties  of  the  materials  have  much  influence  on  the 


122  APPENDICES. 

pig-iron  resulting.  Thus,  for  instance,  very  quartzy  ores  re- 
quire, more  heat  to  cause  the  silica  to  enter  into  chemical 
combination  than  do  those  ores  that  contain  silica  in  chemical 
combination  beforehand.  Quartzy  ores,  therefore,  promote  the 
formation  of  gray  pig-iron. 

To  introduce  the  ash  of  the  fuel  into  our  calculation,  we 
first  calculate  the  burden  from  the  composition  of  the  ores  and 
the  fluxes.  Taking  the  consumption  of  coke  at  thirty-five 
parts  per  one  hundred  parts  of  ores  and  fluxes,  we  calculate 
how  much  coke  is  thus  required  for  the  quantities  of  ore  and 
fluxes  found  from  the  tables  of  equivalents.  Then  we  find 
(p.  74)  how  much  ash  this  quantity  of  coke  gives,  and  further, 
what  part  or  multiple  of  a  coke-ash  equivalent  this  amount  of 
ash  forms.  We  have  then  only  to  introduce  a  corresponding 
part  or  multiple  of  some  ore  or  flux  equivalent  to  flux  the 
coke-ash  in  concordance  with  the  other  burden. 


APPENDICES. 


123 


C/) 

W 

u 


H 

CO 


CQ 


ac 

H 


W 
J 
CQ 
< 

H 

O 
g 

X 
D 


EQUIVALENTS,  OR  AMOUNTS  OF 

ORE,  ETC.,  REQUIRED  TO  GIVE 

i  PART  OF  OXYGEN  IN  EXCESS 
OF: 

.i 
«8d 
»J 

•*0!S 
aq*  uj 

M|    ^ 

•sasBg 
aq;u! 

«)CQ. 

IH 

.y  .. 

•'ois 

aq;u! 

vO                     ?>         .          *N 

LJ  LJLJ: 

r 

•sasng 
sqiuj 

i     «     i      8 
t^. 

Monosili- 
cate  i  :  i. 

>SOIS 
aqiuj 

a   ,    &       g 

O^                   M                   t^. 

•saseg 
aqj  uj 

1   £  '   s  • 

ONE  PART  CONTAINS: 

EXCESS  OF  OXYGEN  ABOVE 

W   4J 

«2 

/t    -ZQ  ig  I 
aq»  uf     |        9  »  —  S  =  /C 

8/  'sasEg 
3qjUI 

S?-grrer 

Bisilicate 
i  :  2. 

•80!S 
aq;  ui 

^   i    S   i    S 

o             o5             o 

•sasng 
sqjuj 

"1               •*• 

*  i  »   |  ' 

Monosili- 
cate  i  :  i. 

•8o?s 

3qjuj 

«                      OO                      OO 

LLJL_! 

•saseg 
aqjuj 

S         8 

1    s-  •    j?  • 

OXYGEN  IN  THE  SLAG-FORMING 
INGREDIENTS. 

-8O  !S  "! 
uaSXxQ 

en 

Z    $>   "%     2    3 

oo        O        tn       «       \O 
O        O        O        O        N 

sasi>g  m 
uaSXxQ* 

« 

M         in       00         O        vO 
N          ^-        OO         CO          t^ 
<^5        00          O          •*         N 

q      o      o      «      M 

•8o  z\v 

vr>                   t^                   iri 

O          .          •*•                   O 
ro        1          0          1          o» 
O                    O                    O 

•0§IM 

o 

1  ?  '   '   ' 

•0*3 

S    S   c8     P. 
1     ?    8    ?    o 

•OUH 

1  I  §  '  ' 

•NOHI 

OO       vO         ro                   O 
N_        N         0_         |          5 

SLAG-FORMING  INGREDIENTS. 

'I^oj, 

OO       00         O         ON        O 
N        n        M        in      oo 

•eo's 

^         M          o5         N          8 

«      q      5      q      »n 

•SQ  8iy 

f     '       1      '      f 

•OSIM 

'      f      '        '        ' 

•0*D 

,52^8 

M         0         ir>        N 

•Ouro 

Iff11 

jj 

I 

I   g   i  |  1 

§      §      §     .6     ^ 

HH         HH         M         hJ         CJ 

& 

>^  » 

g 

O   5 

•c 


N      O     00 

?l  -  J? 


°°°" 

flj       M    II 

fa  w  ^ 

J 

I"  s 


o  °  o 

aS  A 


124 


APPENDICES. 


TABLE  FOR  FACILITATING   THE   RAPID   CALCULATION   OF 
RESULTS    OF   ANALYSIS. 


Weight  of  Pre- 
cipitate ob- 
tained, Grams. 

Five  Grams  of 
Sample  taken 
[Si  0,] 
Si  per  cent. 

Five  Grams  of 
Sample  taken 
[C02] 
C  per  cent. 

Five  Grams  of 
Sample  taken 
[Mn3  04] 
Mn  per  cent. 

Five  Grams  of 
Sample  taken 
[Mg2  P2  07] 
P  per  cent. 

Ten  Grams  of 
Sample  taken 
[Ba  S04] 
S  per  cent. 

.01 

•093 

•0545 

.144 

.056 

•0137 

.02 

.186 

.1090 

.288 

.112 

.0274 

•03 

.279 

•1635 

•432 

.168 

.0411 

.04 

•372 

.2l8o 

.576 

.224 

.0548 

•°5 

.465 

.2725 

.720 

.280 

.0685 

.06 

.558 

.3270 

.864 

•336 

.0822 

.07 

.651 

•3815 

I.OOS 

•392 

.         -0959 

.08 

•744 

.4360 

I.I52 

.448 

.1096 

.09 

.837 

•4905 

1.296 

•5°4 

•1233 

For  example:  in  carbon  determination,  if  the  increase  of  the  potash  bulbs 
is  found  to  be  —  .137 S  grams,  we  have: 
•5450 
•l635 
.0381 
.0027 

•7493  Per  cent  °f  carbon 


APPENDICES.  125 

D. 

ETCHING   TEST   FOR    IRON   AND    STEEL. 

IRON  and  steel  surfaces  are  etched  by  means  of  a  mixture 
of  one  part  of  strong  H  N  O3  with  three  parts  of  strong  H  Cl, 
or  two  parts  of  strong  H  N  O3  with  one  part  of  concentrated 
H2  SO4. 

The  acids  attack  the  softer  parts,  and  parts  rich  in  slag, 
more  vigorously  than  the  metallic  parts.  The  attacked  parts 
appear  soft  and  excavated. 

The  etched  surface  may  be  preserved  by  dipping  it  into 
lime-water  after  treating  with  acid,  washing  with  water,  and 
then  applying  a  thin  coating  of  wax. 


126 


APPENDICES. 

E. 


TABLE   OF   ELEMENTS,  WITH    SYMBOLS    AND    COMBINING 

WEIGHTS. 


NAME. 

SYMBOL. 

COM.  WT. 

NAME. 

SYMBOL. 

COM.  WT. 

Aluminium      .     .     . 
Antimony  .     .     .   -^ 
Arsenic 

Al 
Sb 
As 

27.4 
122 

JC 

Manganese    .     .     . 
Mercury    .     .     .    %  .  j 
Molybdenum 

Mn 
Hg 
Mo 

55 
200 
06 

Barium  
Bismuth      .... 
Boron 

Ba 
Bi 
B 

*37 

2IO 
II 

Nickel.    .    .  ,\    ^  * 
Niobium  .     . 
Nitrogen  .     .     .  *»V* 

Ni 
Nb 
N 

58.7 
94 
14 

Bromine     .... 

Cadmium   .... 
Caesium      .... 
Calcium      .... 
Carbon  

Br 

Cd 
Cs 
Ca 

c 

80 
112 

133 
40 
12 

Osmium    .     .     ..'i 
Oxygen     .     .     .    . 
Palladium     .     .     . 
Phosphorus  .     ... 

Platinum       .    ./  .  -;*' 

Os 
O 
Pd 
P 
Pt 

199.2 
16 
106.6 
3i 
197-5 

Chlorine     .     '    .    . 
Cerium  

Cl 
Ce 

35-5 

02 

Potassium     .     .     . 
Rhodium  .... 

K 
Rh 

39-i 
104.4 

Chromium  .... 
Cobalt 

Cr 
Co 

52-5 
58.7 

Rubidium     .     .     . 
Ruthenium    .     .     . 

Rb 
Ru 

854 
104.4 

Copper  . 

Cu 

63.5 

Selenium  .... 

Se 

79-5 

Didymium  .... 

D 

Q6 

Silver  ..... 
Silicon 

Ag 
Si 

108 

28 

Erbium  
Fluorine     .... 

Glucinum  .... 
Gold           .     .    .  •'* 

E 
F 

Gl 
Au 

112 
J9 

9-5 

1  07 

Sodium     .... 
Strontium     .     .    , 

Sulphur    .  .;.    .    .  r 
Tantalum      .     .     . 

Na 
Sr 
S 
Ta 
TV 

*3 
87.5 

32 
172 

Hydrogen  .... 
Indium  

H 
In 

74 

Thallium 
Thorium  .... 
Tin  

Tl 
Th 

Sn 

129 
204 

1  1  57 
118 

Iodine 

I 

127 

Iridium  
Iron  

Ir 
Fe 

198 

56 

Titanium  .... 
Tungsten  .... 

Ti 
W 

50 
184 

Lanthanum     .     .     . 
Lead 

La 
Pb 

92 

2O7 

Uranium  .... 
Vanadium     .     .     . 

U 
V 

1  20 

137 
£- 

Lithium  
Magnesium     .     .     . 

Li 

Mg 

7 

24 

Yttrium    .... 
Zinc      
Zerconium     .     .    . 

Zn 
Zr 

65.2 
89.6 

APPENDICES.  I27 

F. 

FRENCH   WEIGHTS   AND   MEASURES, 

AS  MOST  FREQUENTLY  REQUIRED   FOR  ENGLISH   COMPARISONS. 


WEIGHTS. 

i  milligramme=     .015438  English  Troy  grains. 
i  gramme         =15.438  "  "          " 

or  .002205  of  a  Ib.  Avoirdupois, 
i  kilogramme  =  2.2048  Ibs.  Avoirdupois. 

WEIGHTS   AS   POPULARLY   ESTIMATED. 

Ibs.  ozs.  drs.  Avoirdupois, 

i  gramme    .     .     .     =     o  o  o£ 

i  decagramme  .     .     =     o  o        5f 

i  hectogramme     .     =     o  3        8£ 

i  kilogramme  .     .     =     2  3  4$- 

LINEAL   MEASURES. 

i  millimetre  .  .  .  =       .039371                English  inches. 

25!  .  .  .  =  i                                   «       inch, 

i  metre  .  .  .  =  39.371  or  39!               "       inches, 

or  =  3.2809  feet  =  3!  inches. 

MEASURES   OF   SURFACE. 

i         centiare  =       1.196  English  square  yards,  or  10.764  English  sq.  ft. 

9.3    centiares  =  100  "  "      feet. 

i       are  =  119.6  "  "      yards. 

40.47  ares  =       i  "       statute  acre. 

I       hectare      =       2.47          "  "        " 

MEASURES   OF   SOLIDITY. 

i  millistere    .    .    ..%. =       .035317  English  cubic  feet. 

i  stere =•  35.317  "  " 

MEASURES   OF   CAPACITY. 
I  litre =  61.028  English  cubic  inches. 

POPULAR   MEASURES   OF   CAPACITY. 

English  galls,  qts.  pts.  imp. 

i  litre =         o  o        if     " 

i  decalitre =         2  o        i£     " 

i  hectolitre .     .  =       22  o        o       " 

i  kilolitre  .                                             .  =     220  o        o       " 


128 


APPENDICES. 


CONVERSION   OF   EQUIVALENT   MEASURES. 


ENGLISH    TO 

FRENCH. 

Inches 

X      o"7  ^4     -—  metres  .     . 

x 

Feet      .    . 

.    X       .  7O477    —        t( 

.     .    X 

Yards 

x     91438  —     " 

x 

Miles 

X    i  6093     —  kilometres 

.     .    X 

Acres   . 

.   X      .40467  —  hectares     .     . 

.    .  x 

Imp.  cralls. 

X   A  cj.'i'iQ  —  litres 

x 

Cubic  inches 

X      01639  —      "         ... 

x 

Bushels    .     , 

.     .  X     .36347  =  hectolitres     . 

.    .  x 

Quarters  .     . 

;-'-,..  x  2.9077  =      «     .  .- 

.    .  x 

Troy  grs. 

.     .   X     .06479  =  grammes    .     . 

.     .    X 

Troy  Ibs.      . 

•     •  x     -3732     ~  kilogrammes  . 

.    .  x 

Avoir.  Ibs.    . 

•    .  x    .4535    = 

.    .  x 

FRENCH   TO   ENGLISH. 

39.371     =  inches. 

3.2809  =  feet. 

1.09364=  yards. 

.62138=  miles. 

2.4712  =  acres. 

.2201   =  gallons. 

61.028     =  cubic  ins. 

2.75125=  bushels. 

•3439  ~  quarters. 

1 5-434     =  Troy  grs. 

2-6795  —  Tr°y  H>s. 

2.2048  =  Avoir.  Ibs. 


APPENDICES.  129 

G. 

'BODY"   IN   STEEL. 

It  has  been  pointed  out  in  the  first  chapter  of  this  book  how 
difficult  it  is  even  with  the  use  of  the  comparatively  accurate 
analyses  of  the  present  time  to  find  the  true  connection  between 
chemical  composition  and  physical  properties  of  steel.  The 
influence  of  minute  quantities  of  impurities  has  been  demon- 
strated in  many  metals  besides  iron,  by  various  scientists.  It 
is  quite  possible  that  the  presence  of  minute  amounts  of  such 
elements  that  are  not  included  in  what  is  generally  termed  a 
"  complete  analysis  "  of  steel  may  cause  some  of  the  wide  dif- 
ferences in  physical  properties  which  are  sometimes  observed 
in  otherwise  similar  steels. 

Be  this  as  it  may,  there  is  something  in  steel  for  which  we 
cannot  account,  and  "  body  "  it  is  called  in  Sheffield  a'nd  in 
Sweden.  The  cast-steel  made  from  the  best  Swedish  steel-iron 
has  more  "  body  "  than  other  cast-steels ;  it  will  stand  a  larger 
number  of  heatings,  etc. 

But  it  is  not  only  the  crucible  steel  that  has  need  of  the 
word  "  body."  Take  for  instance  the  soft  Bessemer  steel  and 
Martin  steel,  at  present  made  in  Sweden,  from  the  same  mate- 
rials as  are  used  for  the  famous  steel-irons.  Horseshoe  nails, 
rivets,  ship  plates,  etc.,  from  this  soft  steel  show  an  endurance 
in  service,  a  "  body,"  that  can  rarely  be  attained  by  steels 
made  from  other  materials  and  "  doctored  "  in  an  open  hearth 
furnace  so  as  to  have  nearly  the  same  chemical  composition. 
Some  manufacturers  using  only  wrought-iron  claim  that  the 
softest  cast-metal  cannot  stand  the  constant  vibrations  suffi- 
ciently, whilst  others  have  abandoned  the  wrought-iron  in 
favor  of  the  soft  metal  made  from  the  "  steel-iron  "  ores. 

The  same  "  body  "  is  noticed  in  the  harder  varieties  of  steel 
9 


13°  APPENDICES. 

made  from  the  old  " steel-iron"  ores.  No  satisfactory  expla- 
nation regarding  this  has  yet  been  reached  ;  but  it  is  hoped 
that  experiments  such  as  those  conducted  by  Mr.  Brinell  (vide 
above)  will  throw  more  light  on  the  subject. 

The  following  analyses  show  the  composition  of  a  soft  Bes- 
semer steel  made  from  the  Swedish  steel-iron  ores  and  a  steel 
made  from  cheaper  ores;  the  steels  are  both  used  for  nails, 
etc. 

I.  Swedish  Ore.  2.  Cheaper  Ore. 

P       =  .027  P      =  .065 

Mn  =  .14  Mn  =  .51 

Si     —  .01  Si    =  .01 

S      =  .01  S      =  .04 

C      =  .10-15  C      =  .11 

The  former  steel  shows  a  decidedly  better  chemical  compo- 
sition than  the  latter,  but  even  when  the  compositions  happen 
to  be  nearly  alike,  the  "  body"  will  assert  itself. 


APPENDICES. 


H. 

MELTING  POINTS,  SPECIFIC    HEAT,  LATENT   FUSING  HEAT  AND 
ELECTRICAL  CONDUCTIVITY   OF   METALS. 


Metals. 

Melting  point. 
Deg.  C. 

Specific  heat. 

Latent  fusing 
heat. 

Conductivity 
Hg  =  ,. 

Al  

700 

.21224 

31.7 

Sb      

4CO 

.04080 

2.O 

As 

O7«;8 

2.6 

Pb  

314 

.0402  fluid 

5.858 

4.8 

Cd          

32O 

0^48 

13.660 

13.0 

Soft  iron 

1600 

.  10808 

8.3 

Pig-iron,  white 
"       gray  . 
Steel 

IO5O-IIOO 
1200-1300 
1300—1400 

U7C 

23  ooo 
33-ooo 

Au 

IO7^ 

0316 

4-1.8 

Co      

I8OO 

10674 

9.6 

Cu 

I2OO 

.0048'; 

121.  2 

C2    2 

Mn  

IQOO 

.  1217 

Ni    

I6OO 

.  10916 

7.q 

Osmium  

2  COO 

.O^II^ 

Palladium  
Platinum  

1500 

I771? 

.0592 
.0^77 

36.30 
27.18 

6.9 

8.2 

lie 

—  -JQ 

O^IN 

2.82 

I.O 

AJ&   • 
Rhodium  
Ruthenium.  .  .  . 
Iridium  . 

2OOO 
I800 
22OO 

.05803 
.06ll 

Oq2^ 

Ae.  . 

QC4 

.O^tjq 

2I.O7 

e;?  .2 

Bi     

260 

.0363  fluid 

12.64 

.8 

Zn 

412 

OQ-J2 

28    13 

16.1 

Sn  

228 

.0637  fluid 

I-J.  -JJ 

8.2 

Cr  

Higher  than  Pt. 

.OQQ7 

Wo  . 

«         «     « 

•  o^^o 

132  APPENDICES. 


I. 


The  accompanying  list  of  Apparatus  and  Reagents  is  in- 
tended to  give  some  idea  as  to  what  is  wanted  in  setting  up  a 
laboratory  for  regular  steel  works  analyses  ;  the  idea  of  putting 
down  the  prices  was  only  a  second  thought.  As  it  is  impossible, 
on  account  of  the  fluctuating  prices  of  articles  like  these,  to  be 
exactly  right,  it  may  seem  rather  out  of  the  way  to  give  any 
price  at  all ;  but  it  is  done  so  as  to  give  some  idea  as  to  what 
such  a  laboratory  could  be  stocked  for,  and  as  the  highest 
price  has  been  given  for  everything,  especially  the  apparatus, 
it  would  perhaps  be  nearer  the  right  amount  if  the  total  were 
to  be  discounted,  say,  25  per  cent,  and  the  place  could  be  fitted 
up  for,  say,  $389.00 ;  this  does  not  include  the  platinum  com- 
bustion apparatus  given  in  this  book,  as  it  stands,  not  counting 
oxygen  receiver,  it  would  cost  about  $100.00.  In  round  num- 
bers it  would  cost  $500.00;  this  would  be  a  well-fitted-up 
laboratory  ready  to  turn  out  any  kind  of  work  usually  done  in 
a  steel  works,  and  with  the  stock  on  hand  should  run  from  four 
to  eight  months,  according  to  the  amount  of  work  required  to  be 
turned  out  in  that  time.  Of  course  the  most  useful  reagents, 
such  as  the  acids  and  ammonium  hydrate,  might  be  required 
before  that,  and  then  other  chemists  might  want  other  things 
which  are  not  mentioned  in  this  list,  and  which  they  would 
consider  highly  important  to  have. 

REAGENTS. 

Acid,  acetic,  5  Ibs.  @  .13 

"    chromic,  I  Ib 


nitric,  49  Ibs. 


$     .65 

2.OO 

* 

7.  5O 

A  Ib 

1.25 

I5.OO 

(cb  ,2*.  . 

12.  '-it 

APPENDICES.  133 

Acid,  oxalic,  -£  Ib $     .40 

"     sulphuric,  18  Ibs.  @  .25 4. 50 

Alcohol ,  I  pt , .60 

Ammonium  chloride,  2  Ibs.  @  .  50 I. oo 

hydrate,  28  Ibs.  @  .15. 4.20 

"         oxalate,  {  Ib 35 

"         carbonate,  £  Ib .35 

Asbestos,  2  Ibs.  @  i.oo 2.00 

Barium  carbonate,  i  Ib 1.70 

"     chloride,  I  Ib... .30 

Bromine,  lib .80 

Calcium  chloride  (dry),  2  Ibs.  @  .75 1.50 

Copper  and  ammonic  chloride,  20  Ibs  ......    18.00 

' '     sulphate  (common),  5  Ibs.  @  .  10 .50 

Iron  sesquichloride,  i  Ib i.oo 

'    protosulphate,  5  Ibs.  @  .  10 .50 

"                "           and  aminon.,  i  Ib .20 

"    sulphide,  2  Ibs.  @  .20 .40 

Iodine,  I  oz .30 

Magnesium  chloride,  I  Ib .50 

Mercury,  I  Ib .65 

Microcosmic  salt,  ^  Ib .70 

Paper,  white  wrapping,  5  qrs.  @  .  30 1. 50 

"       filtering  schleicher  and  schulls,  595,  5  qrs.  @  .60 3.00 

589  cut,  C.  P.  ii  C.  M.  3pck.  @i.io  3.30 

"     "        "       9     "      2    "     @    .90  i. 80 

"     "        "       7     "      4    "     @    .70  2.80 

Potassium  carbonate ,  ^  Ib  . . . .50 

"         bi-chromate,  2  Ibs.  @  .50 i.oo 

' '         chlorate,  5  Ibs.  @  .  50 2.50 

' '         cyanide-ferro,  \  Ib .25 

"       ferri,  i  Ib 50 

"         hydrate  (by  alcohol),  2  Ibs.  @  1.50 3.00 

' '         permanganate,  I  Ib .70 

Pumice  stone,  I  Ib .10 

Silver  nitrate,  ^  oz .50 

Sodium  acetate,  i  Ib .75 

"     carbonate  (dry  C.  P.I.  2  Ibs.  @  .60 1.20 

"     thiosulphate,  2  Ibs.  @  .60. 1.20 


134  APPENDICES. 

Zinc,  metallic  C.  P.  •£  Ib.  . go,  2  Ibs.  common,  @  .  25,  .  50 $  1.40 

Wax,  bees',  £  Ib 30 

"     sealing,  i  Ib .20 


$104.60 
APPARATUS. 

I  Balance,  analytical,  to  weigh  up  to  100  grms.  and  sensible  to  -£3  milli- 
gramme    $  95 .  oo 

i  Balance,  Robervahl  No.  3 7 . 50 

I  set  weights,  50  grms.  and  down  to  I  milligramme,  with  3  riders 16.00 

I     "         "           I  kilo,  to  I  gramme 8.50 

Beakers,  Griffin's  wide  form,  lipped,  1-6  ;  12  nests,  @  $1.85 22.20 

1-3;  12     "       @      .60 7.20 

"      conical  Bohemian  glass,  i  litre  capacity,  12  @      .35 4. 20 

Bellows,  Fletcher's  new  pattern  No.  9,  a  foot  blower 6 .  oo 

Blast  Lamp,  Bunsen  No.  5 3 . 50 

Burners,  Fletcher's  solid  flame  No.  47,  large  size,  3  @  2.00 6.00 

"       Finckner's  improved  form,  6  @  2.00 12.00 

Bottles,  Reagent,  I  pint  glass  stoppered,  I  dozen 2 .00 

I  quart    "          "              I    "     2.50 

common  wide  mouth,  for  drillings,  2  oz.,  4  gross  @  4.20 16. 80 

"      Woulff's  2  necked,  pint,  4  @  . 50 2.00 

Brushes,  camel's  hair,  small,  6 .15 

"     large,  i 05 

Bulbs,  for  sulphur  determination,  Troilius  improved  form,  6 4. 50 

Burettes,  Mohr's,  50  c.c.  grad.  to  -&  c.c. ,  I i .  50 

"      loo  c.c.     "      to-foc.c.,  i 2.50 

Carboys  for  distilled  water,  2@  1.50 3.00 

Condenser,  block  tin  worm,  in  zinc  tank,  to  be  attached  to  steam  pipe 8.00 

Corks,  wooden,  to  fit  drilling  beetles,  4  gross  @  2.00 8 .00 

"         "         assorted,  small,  i  gross 3.50 

*    rubber        "        i  Ib 3.00 

Crucibles,  porcelain,  Royal  Berlin,  No.  oo,  6  @  .  18 i  .08 

"         platinum,  each  20  gr.  4  =  80  grammes  @  .35 28 .00 

Cylinders,  Erdmann,  4  @  .25 i .  oo 

glass,  1000  c.c.  grad.  to  10  c  c.,  ground  stopper,  i 3.00 

"            "         25  c.c.     "     "     i  c.c.,  i .25 


APPENDICES.  135 

Dishes,  porcelain,  pint,  4  @  .  50 , <$  2 .00 

402.  4  @  .25 i. oo 

Files,  4"  A,  4  @  .12 .48 

Flasks,  2  gallon,  I 2 .  oo 

"'  2  qt  ,  6  @  .50 3.00 

"  I  "  12  @  .35  4.20 

"  I  pt.,  6  @  .25  1.50 

"  I  "  ground  stopper,  labeled  from  A  to  L,  12 12.25 

Funnels,  2\  inches,  2  dozen  @  2.25 4. 50 

i?       "       2     "       @  1.75 3-50 

"         4         "       4@.i8 .72 

"        9        "       2@.35 70 

for  filtering  with  asbestos,  I2@.25 3.00 

Glass,  measuring  16.  oz.,  graduated .62 

"     covers,  Watch,  2\",  12 1.25 

4",      12 2.00 

5",    12 2.50 

Hydrometers,  one  for  above  i.ooo  and  one  for  below  i.ooo  @  i.oo 2.00 

jars,  18"   x   if" .60 

Labels,  gummed,  No.  221,  12  boxes  @  .10 1.20 

Reagent,  2  books,  @  .  25 .50 

Mortar,  agate,  3$-"    8.  oo 

"     Wedgewood,  3" .40 

"        5i" 80 

' '     iron,  2  gallon    4.00 

Tongs,  crucible  1.50 

Pipette,  loo  c.  c .70 

"        5oc.c.,2@.50 r.oo 

"         10  c.  c .25 

Platinum  triangles,  4  each  II  grammes  —  44  grammes,  @  .35 15.40 

Plates,  porcelain,  for  testing,  3  @  .65 1.95 

Racks,  test  tube,  2  @  .75 1.50 

Sieves,  copper,  with  mesh,  50  to  I  in.,  and  80  to  I  in.,  2  @.  50 i.oo 

Stands,  burette,  i 1.25 

"      filter,  6  @  i. oo 6.00 

*'      retort  (iron),  with  rings,  6  @  1.25 7.50 

u      tripod,  4  @  .50 2.00 

Thermometers,  360°  Cent.,  2  @  2.00 4.00 

Rubber  finger  tips,  I  doz .50 


136  APPENDICES. 

Tubes,  aspirator,  Geissler's,  2  @  .75 $  1.50 

"  funnel,  stopcock,  2  @  i.oo 2.00 

"  test,  5"  x  f ,  5  doz.,  @  .30 i  50 

"  for  carbon  determination,  I  set 2.50 

"  glass,  assorted,  3  Ibs.  @  .50 i  50 

Rods,         "           "         3  Ibs.  @  .50 1.50 

Rubber  tubing,  vulcanized,  \",  24  ft.,  @  .15 3.60 

"  pure,  £",  12  ft.,  @  .10 i. 20 

"  "  f^,  12  ft.,  @  .14. . 1.68 

i  Desiccator 4.00 

SUNDRIES. 

i  broom,  .35;  i  dust  brush  and  pan,  .50;  scissors,  .75;  hammer,  1.25 2.85 

1  small  magnet,  .25;  clock,  2.00;  camera  for  c.  determination,  2.50 4.75 

2  baths  for  c.  determination,  2.00;  matches,  .25 2.25 

Total  for  Apparatus 414.03 

*'     "   Reagents 104.60 

$518.63 


APPENDICES.  137 

J- 

LIST   OF    THE    PRINCIPAL   IRON   ORES. 

Carbonates  of  iron  (with  carbonates  of  Mn,  Ca  and  Mg) : 

Siderite,  chalybite,  spathic  and  sparry  iron,  steel  ore. 

Spherosiderite,  often  containing  manganese. 

Sideroplesite. 

Siderodot. 

The  crystallized  carbonates  in  layers. 

Earthy,  lithoid,  argillaceous,  and  calcareous  carbonates  of 
iron. 

Clay  Ironstone  (common  name  given  to  many  different 
kinds  of  iron  ores).  (Fe  O3,  A12  O3,  H  O). 

Nodular  carbonates. 

Black  band  iron-stone  of  England. 

Cleveland  iron-stone  of  England. 

Magnetic  Ores  (Ti  O  gangue,  etc.). 

Magnetite. 

Ochreous  magnetite. 

Magnetic  sands. 

Red  Hematites  (H2  O,  gangue  Mn  O,  Cu  O,  A12  O3,  Si3,  P2  Os, 
Ti  O.)  : 

Specular  iron,  oligist  iron,  iron  glance. 

Micaceous  iron. 

Martite. 

Violet  ore. 

Red  ochre. 

Specular  schist. 

Clay  iron-stone,  argillaceous  hematite. 

Puddlers'  ore  from  Cumberland,  England. 

Lenticular  iron  ore,  oolitic  fossil  ore. 

Brown  hematites :  Turgite. 


138  APPENDICES. 

Gothite,  pyrrhosiderite,  brown  iron-stone  or  ore. 

Limonite,  brown  ochre. 

Xanthosiderite. 

Frankliiiites :  (Fe3  O2,  Mn  O,  Ca  O,  Si  O2,  Mg  O,  Zn  O). 

For  the  analysis  of  chrome-iron-ores  and  the  determination 
of  many  rare  elements  by  convenient  methods,  the  reader  is 
referred  to  Roscoe-Schoslemmer's  Chemistry,  Post  and  others. 
It  is  beyond  the  province  of  this  book  to  enter  upon  such 
analyses  as  do  not  occur  in  the  ordinary  routine  of  an  Iron  and 
Steel  Laboratory. 

For  examples  of  analyses  of  iron  ores,  vide  the  Records  of 
the  Geological  Survey  of  Pennsylvania. 


APPENDICES.  1 39 


K. 

/ 

Determination    of  organic    matter  in  water  for 
drinking  purposes.     By  Prof.  Eggertz. 
Requisites : 

=  A  beaker  10  c.  m.  high,  5  c.  m.  wide,  with  a  100  c.  c.  mark. 

=  A  measuring  test  tube,  10  c.  m.  long  and  .9  c.  m.  inside 
diameter ;  graduated  into  I  and  J  c.  c. 
•=  A  glass  rod  12  c.  m.  long. 

=  Pure  concentrated  sulphuric  acid. 

=  Solution  of  .435  gram  pure,  dry,  cryst.  permanganate  of 
potassium  in  1000  c.  c.  of  distilled  water.  Every  c.  c.  of  this 
solution  contains  .1  milligramme  oxygen  for  the  destruction  of 
organic  substances.  The  organic  substances  may  be  of  many 
different  kinds,  requiring  different  amounts  of  oxygen,  but  it 
is  supposed  that  the  total  quantity  of  these  substances  is  =  20 
times  the  amount  of  oxygen  consumed. 

100  c.  c.  of  the  water  for  testing  are  taken  into  the  above- 
mentioned  beaker,  5  c.  c.  of  Ha  SO4  and  3  c.  c.  of  K  Mn  O4  are 
added.  The  beaker  is  then  put  into  a  pot  with  boiling  water  ; 
on  the  bottom  of  the  pot  a  piece  of  cloth  is  placed  for  the 
beaker  to  rest  upon.  The  beaker  is  steadied  by  means  of  a 
triangle  of  brass  or  iron  wire.  The  boiling  water  should  be  on 
the  same  level  as  the  water  in  the  beaker.  After  about  3  min- 
utes the  water  in  the  beaker  has  a  temperature  of  about  90°, 
and  retains  this  as  long  as  the  water  outside  is  kept  at  a  gentle 
boil.  If  after  5  minutes  at  90°  C.  a  red  color  remains  the 
water  may  be  considered  as  good.  If  the  color  disappears 
another  3  c.  c.  K  Mn  O4  are  added.  If  now  after  5  minutes  at 
90°  C.  the  red  color  remains,  the  water  may  be  used  for  drink- 


I4O  APPENDICES. 

ing  purposes.     By  continuing    in  this  manner  the  quality  of 
any  water  may  be  shown. 

The  volume  of  the  water  in  the  beaker  should  be  kept  con- 
stant by  adding  a  little  distilled  water  now  and  then,  as  at  90° 
C.  about  I  c.  c.  is  evaporated  every  minute. 


APPENDICES. 


141 


TABLE    GIVING    THE   TENSION    OF    AQUEOUS    VAPOR   IN    M.    M. 
MERCURY  BETWEEN  o°  AND  40°  C.,  ACCORDING  TO  REGNAULT. 

log.  /  =  a  +  bc\t°  +  cfit°. 
a  =  4-7393707. 

log.  (bat-}  —   +  0.6117408 0.003274463  *>,  (b  negative). 

log.  (cftt°)  —  —  1.8680093  +  0-006864937  ty,  (c  positive). 


u 

/• 

1 
log.  p. 

tJ 

/• 

log.  p. 

o 

4-  600 

O  6627572 

21 

18.494 

1-2670381 

I 

4-940 

0.6936961 

22 

19-659 

.2935630 

2 

5-302 

.7244076 

23 

20.888 

.3198954 

3 

5-687 

•7548931 

24 

22.!84 

-3460375 

4 

6  098 

•785i559 

25 

23-550 

.3719908 

5 

6-534 

.8151954 

26 

24.989 

•3977556 

6 

6.999 

.8450155 

27 

26.505 

•4233355 

7 

7.492 

.8746159 

28 

2S.X02 

.4487305 

8 

8.017 

.9040012 

29 

29.781 

•4739419 

9 

0 

°-574 

•93317" 

30 

3I-S48 

.4989725 

10 

9-165 

.9621263 

31 

33.406 

.5238222 

ii 

9.792 

.9908709 

32 

35-359 

.5484945 

12 

10-457 

1-0194058 

33 

37-4io 

.5729897 

13 

H.i62 

.0477316 

34 

39-565 

.5973082 

14 

II-008 

.0758510 

35 

41-827 

•6214535 

15 

12.699 

.1037660 

36 

44-200 

.6454260 

16 

!3-536 

.1314767 

37 

46.690 

.6692267 

17 

14-421 

.1589861 

38 

49.301 

.6928579 

18 

IS-357 

.1862950 

39 

52.038 

.71632:2 

19 

16.346 

.2134062 

40 

54-906 

.7396162 

20 

I739I 

.2403204 

142 


APPENDICES. 


M. 

USEFUL   TABLES. 
TABLE   OF   THE   WEIGHT   OF   BAR   IRON. 


SQUARE. 


Length,  one  foot. 

Length,  one  foot. 

Side  of 

Side  of 

square  in 

square  in 

inches. 

Weight  in 
pounds. 

Cubic  weight 
in  pounds. 

inches. 

Weight  in 
pounds. 

Cubic  weight 
in  pounds. 

i 

.209 

.0174 

9\ 

15-083 

257 

| 

.470 

.0391 

24 

16.909 

.409 

£ 

•835 

.0696 

2i 

18.840 

•570 

|- 

I-305 

.1087 

a 

20.875 

•739 

| 

1.879 

-1565 

2f                    23.115 

.926 

£ 

2.558 

.2131 

2| 

25.259 

2.105 

in. 

3-340 

.2783 

2| 

27.608 

2.301 

1 

4.228 

•3523 

3  in. 

30.070 

2.506 

I 

5-219 

-4349 

3i 

35-279 

2.940 

|^ 

6.315 

.5262 

3* 

40.916 

3-409 

£ 

7  5i6 

.6263 

3f 

46.969 

3-9J4 

I 

8.820 

•7350 

4  in. 

53-440 

4-455 

a. 

4 

10.229 

.8524 

4 

67-637 

5.636 

I 
8 

n-743 

.9786 

5  in. 

83-510 

6-959 

2  in. 

13-360 

1.113 

TABLE  OF   SPECIFIC   GRAVITIES. 


Metals. 

Weight,  water 
being  1000. 

Number  of  cubic 
inches  in  a  pound. 

Weight  of  a  cubic 
inch  in  pounds. 

Platina   

IQ^OO 

I.4I7 

.7053 

Pure  fifold 

102^8 

I   4.^ 

6965 

Mercury          .       .      ... 

13560 

2.04 

•  4QO2 

Lead  

113^2 

2-435 

.4105 

Pure  silver 

IO474. 

2  6^8 

.3788 

Bismuth             

082^ 

2.814 

.3552 

8788 

3-  J46 

.3178 

Brass 

7824. 

0     C-5-5 

.3036 

Iron    cast         

7264. 

3.806 

t 
.263 

Iron,  bar.  ...        

77OO 

3-5Q2 

.279 

Steel 

78q-l 

^      CrtQ 

.2833 

Tin 

72QI 

^.  7QO 

.2636 

Zinc... 

7IQO 

3.845 

.26 

APPENDICES.  143 

APPROXIMATE   WEIGHTS   FOR   PRACTICAL   PURPOSES. 


Specific  gravities. 

Weight  of  a  cubic 
inch  in  pounds. 

We'ght  of  a  cylindri- 
cal inch  in  pounds. 

Iron    cast       

72O7 

.2608 

.2048 

Iron,  bar  

77OO 

.2785 

.2187 

Steel 

78qq 

.28-^^ 

•2225 

Copper  

8878 

.  ^211 

.2522 

Brass   cast  

8306 

.3037 

.2385 

Zinc    common 

7O28 

2^4.2 

Ioq6 

Lead 

II3C2 

.4106 

•  3221; 

Tin,  cast  

7291 

.2637 

.2071 

TABLE    OF     THE    WEIGHT    OF    FLAT    BAR,    HOOP,    PLATE,    AND 

SHEET   IRON. 

Weight  of  a  Lineal  Foot  of  Flat  Bar  and  Hoop  Iron  in  pounds. 


Thickness  in 


Breadth  in  inches. 


inches. 

3i- 

3 

2| 

2* 

ai 

2 

i! 

4 

Ii 

I 

t 

* 

1.47 

1.26 

I-  15 

1.05 

.094 

.084 

•073 

.063 

.052 

.042 

.031 

* 

2.20 

2  94 

1.89 
2.52 

i-73 
2.31 

1-57 

2.10 

i  41 

1.89 

1.26 

T.68 

1.  10 

1.47 

.094 
1.26 

.078 
1.05 

.063 
.084 

.047 
.063 

1 

4.41 

3.78 

3  46 

3-15 

2.83 

2.52 

2.20 

i.89 

1-57 

1.26 

094 

i 

5-88 

5-04 

4.62 

4-20 

3.78 

3.36 

2  94 

2.22 

2.10 

1.68 

1.26 

1 

7-35 

6.30 

5-77 

5-25 

4.72 

4.20 

3-67 

3-15 

2.62 

2.10 

1-57 

1 

8.82 

7  56 

6-93 

6.30 

5.66 

5-04 

4.41 

3-78 

3-15 

2.52 

1 

10.29 

8.82 

8.08 

7-35 

6.61 

5-88 

5-14 

4.41 

3-67 

2.94 

I  in. 

11.76 

10  08 

9.24 

8.40 

7-56 

6.72 

5.87 

5.04 

4.2O 

Weight  of  a  Square  Foot  of  Plate  Iron  in  pounds. 


Thickness  in  parts  of  an  inch.  .  .  .  i 
Weight  it  pounds    5 

•A-     k    -f-6    f 

7^     10    1  2^    15 

I          l         -Sr        £ 
1  (f        ^         lt>         » 

177    2O     22^-      25 

1  1     a 

16       4 

7 

Weight  of  Square  Foot  of  Sheet  Iron  in  pottnds. 


Number  on 
wire  gauge, 

•      I           2 

3 

4 

5 

6        7 

8 

9          10 

II 

and  weight 
in  pounds. 

12.5     12 

ii 

10 

9 

8       7-5 

7 

6        5.68 

5 

Number  on 
wire  gauge, 

•    12       13 

14 

15 

16 

17       18 

19 

20           21 

22 

and  weight 
in  pounds. 

4.62  4.32 

4 

3-95 

3 

2.5     2.18 

i-93 

1  62    1.5 

i-37 

BOOKS    OF   REFERENCE. 


LEDEB u R,  Eisenhilttenkunde. 
EGGERTZ,  Jernkontorets  Annaler. 

Transactions  American  Institute  Mining  Engineers. 

Jernkontorets  A  nnaler. 

Journal  British  Iron  and  Steel  Institute. 
POST,   Chemische  Unterstichungs  Methoden. 
THORPE,   Quantitative  Analysis. 
BAILEY,   Chemists'  Pocketbook. 
BALLING,  Metallhuttenkunde. 
Ho  ARE,  Iron  and  Steel. 

JUPTNER  VON  JONSTORFF,  Eisenhuttenchemiker. 
BECKERT,  Eisenhuttenkunde. 
FRED.  TAYLOR,  Ziemens  Gas  vs.  Watergas. 


LIST   OF   CHEMISTS, 

WHOSE  NAMES  ARE  ASSOCIATED  WITH  METHODS  GIVEN    IN  THIS  BOOK, 


Carbon  by  Combustion MCCREATH,  ULLGREN. 

"       "  Color    EGGERTZ,  JENKINS,  SNELUS. 

Phosphorus TAMM,  SNELUS. 

Manganese BEILSTEIN  and   JAWEIN,  PATTIN- 

SON,  FORD. 

Iron  by  Ki  and  Hg MORRELL,  THORPE. 

Arsenic LUNDIN. 

Tungsten. '." EGGERTZ. 

Gas  Analysis BUNTE,  EGGERTZ,  and  others. 


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